88 



HUTCHISONS 

PHYSIOLOGY 

and HYGIENE 



MAYNARD,MERRILL,& CO. 




flass GPPftfi 



Book 



' I I 



_ 



" 



Copyright^ 10 . 



COPYRIGHT DEPOSIT. 



NEW EDITION. 1902 



A TREATISE 



ON 



PHYSIOLOGY AND HYGIENE 

FOR EDUCATIONAL INSTITUTIONS 
AND GENERAL READERS 

jfrills Illustrate* 



BY 



JOSEPH C. HUTCHISON, M.D., LL.D. 

EX-PRESIDENT OF THE NEW YORK PATHOLOGICAL SOCIETY, EX VICE-PRESIDENT O* 

THE NEW YORK ACADEMY OF MEDICINE, SURGEON TO THE BROOKLYN 

CITY HOSPITAL, LATE PRESIDENT OF THE MEDICAL SOCIETY 

OF THE STATE OF NEW YORK, ETC., ETC. 




NEW YORK 
MAYNARI), MERRILL, & CO. 

190* 



THE LIBRARY OF 
CONGRESS, 

Two Copies Received 

JUL. 2 1902 

-Copyright entry 

CLASS £-XXc. No 

COPY B. 



COPYRIGHT, 1895, 1902. 

BY 

Maynard, Merrill, & Co. 



TO MY WIFE 



WHOSE SYMPATHY HAS, FOR MORE THAN TWENTY YEARS, 
LIGHTENED THE CARES INCIDENT TO 



AN ACTIVE PROFESSIONAL LIFE 



THIS HUMBLE VOLUME 



IS AFFECTIONATELY INSCRIBED. 



PUBLISHERS' NOTE TO REVISED EDITION 

The sales of this work have in the last few years become so large that 
it has been found necessary to make new electrotype plates. The pub- 
lishers have taken advantage of this to have the book carefully examined 
with a view to discovering whether or no it conformed in every respect 
to the latest advances in knowledge of the subject. Very few changes 
in the text have been found necessary, and these few are of such a minor 
character as not in any way to prevent the use of the new and old 
editions in the same class. 

The main changes to be noted in this edition are as follows : Topical 
Outlines have been added at the end of chapters, which it is believed will 
be of great value to pupils and teachers. In some of them additional 
information has been given, which it has not been thought best to include 
in the text, but which may be found useful for the teacher in his class 
work. 

Such slight changes have been made in the text as were necessary to 
meet the requirements of the laws of the several states with respect to 
the influence of alcohol and narcotics. The book will be found to comply 
fully with all such laws and with the intelligent temperance sentiment of 
the country. 

A chapter on emergencies has also been added, which, it is hoped, will 
give the book a permanent value in the home and be of service to the 
many "first aid to the injured" classes that are being formed in all parts 
of the country. 

A number of new illustrations have been scattered through the book. 
The only other change of any prominence is in the experiments, which in 
the former edition have been in the appendix, but are now transferred to 
the body of the book as footnotes, where they will be more accessible as 
an aid to the teacher in more interestingly presenting the subject to the 
class. All the experiments, as well as the anatomical demonstrations, 
are simple, and the teacher will have no difficulty in reproducing them. 
Should there be failure at first, a little patience and a few trials will soon 
be followed by success. All complex dissections on recently killed 
animals, as well as all vivisections upon frogs, etc., have purposely been 
omitted, not only because they are unnecessary in teaching the rudiments 
of anatomy and physiology, but also because they would create disgust 
and abhorrence in the majority of pupils. 

The publishers gratefully acknowledge their indebtedness to D. L. 
Bardwell, Superintendent of Public Instruction, Bingham ton, New York, 
who has made such changes in the text as were necessary to bring it into 
perfect accord with the latest Syllabus of the Board of Kegents of the 
State of New York. 

New York, May 15, 1902. 



PREFACE 



This work is designed to present the leading facts and 
principles of human physiology and hygiene in clear and 
concise language, so that pupils in schools and colleges, and 
readers not familiar with the subjects, may readily compre- 
hend them. Anatomy, or a description of the structure of 
an organ, is of course necessary to the understanding of its 
physiology, or its uses. Enough of the former study has, 
therefore, been introduced to enable the pupil to enter intel- 
ligently upon the latter. 

Familiar language, as far as practicable, has been em- 
ployed, rather than that of a technical character. With a 
view, however, to supply what might seem to some a defi- 
ciency in this regard, a Pronouncing Glossary has been added, 
which will enable the inquirer to understand the meaning 
of many scientific terms not in common use. 

In the preparation of the work the writer has carefully 
examined all the best material at his command, and freely 
used it; the special object being to have it abreast of the 
present knowledge on the subjects treated, as far as that is 
possible in a work so elementary as this. The discussion of 
disputed points has been avoided, it being manifestly inap- 
propriate in a work of this kind. 

The aim of a text-book on physiology for schools and col- 
leges should be to present in the simplest and clearest pos- 
sible manner the well-established facts of the subject to be 
taught, so that the students may obtain an intelligent idea oJ 
the workings and uses oi' the human body. It should be 

6 



6 PREFACE 

scientific enough to be clear and logical, and to appeal to 
reason, not a mere compilation of facts to be learned by rote. 
To make it preparatory to a higher course in physiology 
would be manifestly a mistake, for it would necessitate a 
much more scientific plan of arrangement, and the introduc- 
tion of an amount of material which would be confusing. 
The teaching of anatomy and physiology in schools should be 
considered chiefly as an aid in teaching hygiene, so that the 
student may learn how to live a healthful life. 

The writer desires to acknowledge his indebtedness to E. M. 
Wyckoff, M.D., for valuable aid in the preparation of the 
manuscript for the press; and to R. Cresson Stiles, M.B., a 
skillful microscopist and physician, for the chapter "On the 
Use of the Microscope in the Study of Physiology." 



CONTENTS 



INTRODUCTORY CHAPTER 

CELL STRUCTURE 

Divisions — Cells — Structure of the Cell — Cell Reproduction — Cell 
Nourishment — Cell Motion 

CHAPTER I 

THE FRAMEWORK OF THE BODY 

PAGE 

The Bones — Their Form and Composition — The Properties of Bone 

— The Skeleton — The Joints — The Spinal Column— The 
Growth of Bone — The Bepair of Bone — Changes in the Skele- 
ton — Erect Position 17 

CHAPTER II 

THE MUSCLES 

The Muscles — Flexion and Extension — The Tendons — Contrac- 
tion — Physical Strength — Necessity for Exercise — Its Effects — 
Forms of Exercise — Walking — Biding — Gymnastics — Open- 
air Exercise — Excessive Exercise — Sleep — Recreation. ... 33 

CHAPTER III 

THE INTEGUMENT, OR SKIN 

The Integument — Its Structure — The Nails and Hair — The Com- 
plexion — The Sebaceous Glands — The Perspiratory Glands — 
Perspiration and its Uses — Importance of Bathing — Different 
Kinds of Baths — Manner of Bathing — The Benefit of the Sun 

— Importance of Warm Clothing — Poisonous Cosmetics ... 50 

CHAPTER IV 

THE CHEMISTRY OF FOOD 

The Source of Food — Inorganic Substances — Water — Salt — 
Lime — Iron — Organic Substances — Albumen, Fibrin, and 
Cascine — The Fats or Oils — The Sugars, Starch, and Gum — 
Stimulating Substances — Necessity of a Regulated Diet . . . 76 

7 



CONTENTS 



CHAPTER V 

FOOD AND DRINK 

PAGE 

Necessity for Food — Waste and Repair — Hunger and Thirst — 
Amount of Food — Renovation of the Body — Mixed Diet — Milk 

— Eggs — Meat — Cooking — Vegetable Food — Bread — The 
Potato — Fruits — Purity of Water — Action of Water upon Lead 

— Coffee, Tea, and Chocolate — Effects of Alcohol 91 

CHAPTER VI 

DIGESTION 

The Principal Processes of Nutrition — The General Plan of Di- 
gestion — Mastication — The Teeth — Preservation of the Teeth 

— Insalivation — Hie Stomach and the Gastric Juice — The Move- 
ments of the Stomach — Gastric Digestion — The Intestines — The 
Bile and Pancreatic Juice — Intestinal Digestion — Absorption by 
Means of Blood-vessels and Lacteals — The lymphatic or Absorb- 
ent System — The Lymph — Conditions which affect Digestion — 
The Quality, Quantity, and Temperature of the Food — The Influ- 
ence of Exercise and Sleep — The Kidneys — The Spleen — Effect 

of Alcohol upon Digestion, the Liver, and Kidneys 117 

CHAPTER VII 

THE CIRCULATION 

The Blood — Its Plasma and Corpuscles — Coagulation of the Blood 

— The Uses of the Blood — Transfusion — Change of Color — 
The Organs of the Circulation — The Heart, Arteries, and Veins 

— The Cavities and Valves of the Heart — Its Vital Energy — 

— Passage of the Blood through the Heart — The Frequency and 
Activity of its Movements — Tlie Pulse — The Sphygmograph — 
The Capillary Blood-vessels — The Rate of the Circulation — As- 
similation — Injuries to the Blood-vessels — Effects of Alcohol 
upon the Heart — As a Fat- Producer 151 

CHAPTER VIII 

RESPIRATION 

The Objects of Respiration — The Lungs — The Air Passages — 
The Movements of Respiration — Expiration and Inspiration — 
The Frequency of Respiration — Capacity of the Lungs — The 



CONTENTS 9 

PAGB 

Air we Breathe — Changes in the Air from Bespiration — Changes 
in the Blood — Interchange of Gases in the Lungs — Comparison 
between Arterial and Venous Blood — Bespiratory Labor — Im- 
purities of the Air — Dust — Carbonic Acid — Effects of Impure 
Air — Nature" 1 s Brovision for Burifying the Air — Ventilation — 
Animal Heat 187 



CHAPTER IX 

THE NERVOUS SYSTEM 

Animal and Vegetative Functions — Sensation, Motion, and Volition 

— The Structure of the Nervous System — The White and Gray 
Substances — The Brain — Its Convolutions — The Cerebellum 

— The Spinal Cord and its System of Nerves — The Anterior 
and Bosterior Boots — The Sympathetic System of Nerves — The 
Broperties of Nervous Tissue — Excitability of Nervous Tissues — 
The Functions of the Spinal Nerves and Cord — The Direction 
of the Fibres of the Cord — Beflex Activity and its Uses — Ihe 
Functions of the Medulla Oblongata and the Cranial Ganglia — 
The Beflex Action of the Brain — Effects of Alcohol, Tobacco, 
Snuff, Narcotics, Opium, Chloral, Hasheesh, Chloroform . . . 217 



CHAPTER X 

THE SPECIAL SENSES 

The Broduction of Sensations — Variety of Sensations — General 
Sensibility — Bain and its Function — Special Sensation, Tuck, 
Taste, Smell, Sight, and Hearing — The Hand, the Organ of 
Touch — The Sense of Touch — Delicacy of Touch — Sensation 
of Temperature and Weight — The Tongue, the Organ of Taste 

— The Nerves of Taste — The Sense of Taste, and its Beta t ions 
with the other Senses— The Influence of Education on the Taste 

— The Nasal Cavities, or the Organs of Smell — The Olfactory 
Nerve — The Uses of the Sense of Smell — The Sense of Sight — 
Light — The Optic Nerve — The Eyeball and its Coverings — The 
Function of the Iris — The Sclerotic, Choroid, and Retina — The 
Tears and their Function — The Movements of the Eyeball — 
The Function of Accommodation, — The Sense of II"' ring and 
Sound — The Ear, or the Organ of Hearing — The External, 
Middle, and Internal Ear 864 



10 CONTENTS 

CHAPTER XI 

THE VOICE 

PAGE 

Voice and Speech — The Larynx, or the Organ of the Voice — The 
Vocal Cords — The Laryngoscope — The Production of the Voice 

— The Use of the Tongue — The Different Varieties of Voice — 
The Change of Voice — Its Compass — Purity of Tone — Ven- 
triloquy 321 

CHAPTER XII 

THE USE OP THE MICROSCOPE IN THE STUDY OF PHYSIOLOGY 

The Law of Tissues — Necessity of the Microscope — Different Kinds 
of Microscopes — Additional Apparatus — Preliminary Studies — 
The Study of Human Tissues — Tissues of the Inferior Animals 

— Incentives to Study 333 

CHAPTER XIII 

FIRST HELP IN ACCIDENTS 

Shock — Fainting — Vertigo — Hemorrhage — Fractures and Dislo- 
cations — Sprains — Burns and Scalds — Danger from Illumi- 
nating Gas and Kerosene — Frost-Bites — Sunstroke — Fits or 
Convulsions — Drowning — Poisons and their Antidotes . . . 342 

CHAPTER XIV 

BACTERIA AND DISEASE 

Bacteria — Cause Disease — Require Warmth and Moisture — Varie- 
ties of Bacteria — Toxines and Ptomaines — Antitoxine— De- 
struction of Bacteria , . 355 

APPENDIX 

Care of the Sick-room .......... 343 

Disinfection 345 

Home and Health , 347 

On Going into the Country 349 

Exercises for Home Gymnastics ........... 351 

Glossary 354 

Index „ . , 365 



LIST OF ILLUSTRATIONS 



PIG. 

Frontispiece 

Viscera in Position paqk 

1. Section of bone 19 

2. The skeleton 20 

3. Structure of bone, magnified 21 

4. Section of bone, parallel to surface 21 

5. Ribs in natural and healthy state 22 

6. Ribs showing effects of tight lacing .22 

7. The ligaments of the wrist 24 

8. Cells of cartilage 24 

9. Elbow-joint 25 

10. Spinal column 26 

11. The muscles 32 

12. Muscular tissue, magnified 33 

13. Biceps muscle of the arm 34 

14. Muscles and tendons of the hand . . . . . .37 

15. Lower portion of the leg ., . 37 

16. View of knee-joint 38 

17. The chest weight 48 

18. Root and transverse section of hair, magnified .... 58 

19. Magnified hair and section of skin 60 

20. Magnified view of sweat-gland and duct . . . .61 

21. Granules of potato starch 86 

22. Section of the trunk 119 

23. Section of a tooth 120 

24. Section of the jaws 121 

25. Section of the jaws — right side 122 

26. Structure of a salivary gland 124 

27. Head of a horse, showing salivary gland, etc 125 

28. Section of chest and abdomen 129 

29. Alimentary canal 130 

30. Thelacteals 138 

31. Intestinal villi, magnified 141 

32. The kidneys and bladder 144 

33. Blood corpuscles, highly magnified 162 

34. Blood corpuscles of man and lower animals, magnified . . 153 

11 



12 



LIST OF ILLUSTRATIONS 



lOpp 



osite 



FIG. 

35. Circulation of the blood, 

36. External view of the heart, 

37. Section of the heart ..... 

38. Valves of heart with walls relaxed 

39. Valves of heart during contraction of ventricles 

40. Left section of the heart, | 

41. Eight section of the heart, j * ^ 

42. Form of the pulse 

43. Vein with valves open 

44. Vein with valves closed 

45. Web of frog's foot, magnified 

46. Margin of frog's web . 

47. Organs of the chest 

48. Larynx, trachea, and bronchial tubes 

49. Diagram and section of the air-cells 

50. Section of the lungs . 

51. Section of mouth and throat 

52. Ciliated cells 

53. Ventilation by window 

54. Cerebro-spinal system 

55. Upper surface of the cerebrum 

56. Vertical section of the brain 

57. Lower surface of the brain 

58. Brain and spinal cord . 

59. Section of spinal cord . 

60. Illustrating the functions of the spinal 

61. An experiment with sense of touch 

62. Section of nasal cavity 

63. Front view of the eye . 

64. Vertical section of the eye, magnified 

65. Front section of eyeball 
60. Diagram of blind point of the eye 

67. The retinal image 

68. The different shapes of the globe of the eye 
09. The function of accommodation 

70. The ear and its different parts 

71. Showing the internal mechanism of th 

72. Section of the right ear 

73. Section of the larynx and trachea 

74. A view of the vocal cords by means of 

75. The different positions of the vocal cor 

76. Double convex and plano-convex lenses 

77. Simple microscope 

78. Compound microscope 



e ear, magnified 



the laryngoscope 
ds . 



PHYSIOLOGY AND HYGIENE 



INTRODUCTORY CHAPTER 

CELL STRUCTURE 

Divisions — Cells — Structure of the Cell — Cell Reproduction — ■ Cell 
Nourishment — Cell Motion 

1. Divisions. — The study of the human body includes : 

1. Anatomy, which is the study of the structure of the 
human body. This is again subdivided into, first, gross 
anatomy, which is the study of the structure of the body as 
made by careful dissection; and, second, microscopic anatomy, 
also called histology, which is the minute study of the various 
tissues and organs composing the body, by the aid of the 
microscope. 

2. Physiology, which is the study of the functions of the 
various organs and tissues of the body. 

3. Hygiene, which is the study of the best means of pre- 
serving the body's health. 

2. Cells. — If we examine a portion of any one of the struc- 
tures of the human body under the microscope, we find that it 
is composed of countless small bodies, which are called cells. 
These cells have distinctive shape, size, and form, in each of 
the different structures. Each one of the cells aids in the 
function which characterizes its tissue; thus, for instance, the 
many muscle cells composing one of the muscles oi' the arm 
contract, and their united contraction causes the entire muscle 
to contract. And, again, of the many cells composing the liver, 
each aids in secreting its small portion of bile, and in perform- 
ing its other functions. 

]. What is anatomy ? Physiology ? Hygiene J 2. What are oells ? 
18 



14 CELL STRUCTURE 

3. Although the different cells composing the many tissues 
of the body are all distinct in their respective characteristics, 
they are yet all dependent upon each other for the proper per- 
formance of their work, just as the individual persons compos- 
ing the population of a large city lead independent lives, yet 
are all dependent upon each other for their respective exist- 
ences. Each ceil has a life of its own ; it eats, digests, moves, 
and reproduces its own kind, and yet it is dependent for its 
health and life upon the healthy performance of the functions 
of all the other cells of the body. 

4. Structure of the Cell. — As the type of the simplest cell 
structure, we have the best illustration in a microscopical ani- 
mal, found in stagnant water, and called the Amoeba. It is 
composed of transparent, jelly-like material, enclosed in a very 
thin membrane, and having a more or less irregular shape. 
In its interior we see that a small portion of its jelly-like 
material is more opaque than the rest, as if composed of a 
number of granules. If we observe this Amoeba under the 
microscope, we shall notice that it has life, as manifested by 
its power to contract in places, and in other places to project a 
part of its body. It feeds by enclosing within its substance 
any particles which it may take for food. It retains them in 
its interior until it has absorbed therefrom what it can use, 
when it again partly opens itself at some point near the par- 
ticle, and rejects or moves away from what it does not want. 
It propagates itself by a simple process of subdivision ; that 
is, it divides itself into two unequal portions, each portion 
retaining some of the granular matter, which seems to be 
essential to its existence. 

5. All the cells of the human body have the following 
essential structure : First, a thin membrane enclosing the cell, 
called the cell wall. Second, a jelly-like or granular material, 
composing its body, called protoplasm, and embedded in this 
body a more or less round or oval body of firmer consistency 
than the cell mass, called the nucleus, which, in many cases, 

3. Describe cell life. 4. The structure of the cell. 5. In what does the essential struc- 
ture of the cell consist ? 



CELL STRUCTURE 15 

contains a still smaller body, or minute point, called the 

nucleolus. 

6. The yolk of a common hen's egg probably illustrates this 
best. If we break the egg into a saucer, being careful not to 
break the yolk, we shall find upon examination that the yolk 
is held together by a thin and delicate membrane, the cell 
wall. The liquid portion of the yolk is the protoplasm. And 
we can also readily see, upon careful inspection, a compara- 
tively small speck, more opaque, or rather whitish in ap- 
pearance, which is the nucleus. The nucleolus cannot be 
observed by the naked eye. The following diagram of the 
yolk will illustrate these facts : 




b, Protoplasm, 
a, Cell Wall. 



7. Cell Reproduction. — The following series of diagrams 
shows how simple the process of cell reproduction is. In a 
we have a simple cell ; in b it has changed its shape by elon- 
gating and constricting in its centre; in c the same process 
has been continued; and in d we have two new cells, but no 
parent. The identity of the parent has been lost in its off- 
spring. 




8. Cell Nourishment. — The cell wall absorbs nourishment, 
which soon becomes a part of the general protoplasm. Waste 
products in a similar manner are expelled through the cell 
wall. Some cells have the power of excreting from their food 

6. Describe the four parts of a cell. 1. Describe the process of cell reproduction. 
8. How is nourishment obtained J Waste products expelled ? 



10 CELL STRUCTURE 

a hard substance, called lime, and depositing the same as a 
kind of shell around themselves. 

9. Cell Motion. — It is reasonable to suppose that many of 
the cells of the human body are capable of some motion, 
although this cannot be demonstrated, except in very few in- 
stances. It is easy to demonstrate that the white corpuscles 
of the blood are capable of independent motion, very similar 
to that of the Amoeba. They are able to push their way 
through the walls of the capillaries, and thus wander through 
all parts of the body. 

y. Wliat range of motion has a ceil.' 1 



CHAPTER I 

THE FRAMEWORK OF THE BODY 

The Bones — Their Form and Composition — The Properties of Bone 
— Histology — The Skeleton — The Joints — The Spinal Column — 
Cartilage — The Growth of Bone — The Repair of Bone — Changes 
in the Skeleton — Erect Posture 

1. The Bones. — The framework which sustains the human 
body is composed of the bones. The superstructure consists 
of the various organs on which the processes of life depend. 
These organs are soft and delicately formed, and, if unprotected, 
would, in most cases, rapidly be destroyed when subjected to 
violence, however slight. The bones, having great strength 
and power of resistance, afford the protection required. 

2. The more delicate the organ, the more completely does 
Nature shield it. For example : the brain, which is soft in 
structure, is enclosed on all sides by a spherical box of bone ; 
the eye, though it must be near the surface of the body to 
command an extensive view, is sheltered from injury within 
a deep recess of bone ; the lungs, requiring freedom of motion 
as well as protection, are surrounded by a large "chest" of 
bone and muscle. The bones serve other useful purposes. They 
give permanence of form to the body, by holding the softer 
parts in their proper places. They assist in movement, by 
affording points of attachment to those organs which have 
power of motion — the muscles. For all movements of the 
body as a whole, and for nearly all movements of parts of the 
body, save those controlling the vital processes, the bones are 
levers. 

3. The Form and Composition of the Bones. — The shape and 
size of the bones vary greatly in different parts of the body, 
but generally they are arranged in pairs, one for each side of 



l. The framework of the body ? The superstructure f -. Use of bon< 
17 



18 THE FRAMEWORK OF THE BODY 

the body. Some bones are long and cylindrical, like the 
humerus; some are short and thick, like the bones of the 
wrist; some are flat and thin, like the bones of the skull; 
some are irregular in shape, like the vertebrae. The longest 
bone of the human body is the femur, which may be as much 
as eighteen inches in length ; from this the size of different 
bones varies greatly all the way to the tiny bones in the middle 
ear. Bones are composed of both mineral and animal matter, 
united in the proportion of two parts of the former to one of 
the latter. The mineral matter is chiefly phosphate of lime; 
the animal matter is gelatin. We may separate each of these 
substances from the other for examination. First, if we burn 
a bone for several hours on a good bed of coals, the gelatin is 
entirely removed. There remains a beautiful white specimen 
of phosphate of lime, which preserves the shape of the bone 
perfectly, but is brittle and incapable of sustaining any con- 
siderable weight. To remove the mineral matter we use acid. 
A sheep's rib, thoroughly cleaned, or bones from a roast fowl, 
should be allowed to stand in dilute muriatic acid (one part 
acid to eight parts water) for two or three days, when the 
phosphate of lime will be dissolved and only the gelatin 
remain, but as before, the shape of the bone is preserved, 
the bone being now, however, soft and pliable. The specimen 
may be preserved in alcohol. 

4. If, for any reason, either of these ingredients is dispro- 
portionate in the bone during life, the body is in danger. The 
mineral substance is useful in giving rigidity of form, while 
the animal substance insures toughness and elasticity, so that 

1. Some Properties of Bone. — " The power of bone to resist decay is 
remarkable. Fossil bones deposited in the ground long before the appear- 
ance of man upon the earth have been found by Cuvier, exhibiting a 
considerable portion of cartilage. The jaw of the Cambridge Mastodon 
contained over forty per cent of animal matter — enough to make a good 
glue — and others about the same. From this we see that a nutritious 
soup might be made from the bones of animals that lived before the 
creation of man. The teeth resemble bone in their structure, but resist 
decay longer ; they are brought up by deep-sea dredging, when all other 
parts of the animal have wasted away. The bones differ at different ages, 

3. Shape of bones ? Size ? Composition ? 4. Animal and mineral substance ? 



THE FRAMEWORK OF THE BODY 



19 



by their union we are able to withstand greater shocks than 
would be possible with either alone. In youth, the animal 
portion is in excess; a bone then does not break so readily, 
but, when broken, unites with great rapidity and strength. 
On the other hand, the bones of old persons are more easily 
broken, and in some cases fail to unite. The mineral matter 
being then in excess indicates that the period of active exer- 
tion is drawing to a close. {Read Note 1.) 

5 The Structure of the Bones. — If we examine one of the 
long bones, which have been sawed through lengthwise, we 




Section of Bone.— A, Longitudinal. 
B, Transverse 



observe that it is admirably fashioned for affording lightness 
as well as strength (Fig. 1). Its exterior is hard and resisting, 
but it is porous at the broad extremities, while through the 
central portion there is a cavity or canal which contains an 
oily substance called marrow. The broad extremities furnish 
abundant surface for the formation of joints and for the 
attachment of muscles ; they are porous so that weight may 



and under different social conditions. In the disease called ' rickets,' 
quite common among the ill-fed children of the poor in Europe, but some- 
what rare in America, there is an inadequate deposit of the mineral 
substance, rendering the bones so flexible that they may be bent almost 
like wax. In females and weak men the bones are light and thin, while 
in a powerful frame they are dense and heavy. Exercise is as necessary 
to the strength of bone as to the strength of muscle ; if a limb be disused, 
from paralysis or long sickness, the bones lose in weight and strength as 
well as the soft parts. Bone is said to be twice as strong as oak, and. to 
crush a cubic inch of it, a pressure equal to 5000 pounds is requisite." 



5. The structure of the bones ; 



20 



THE FRAMEWORK OF THE BODY 




Fig. 2.^ The Skeleton 



THE FRAMEWORK OF THE BODY 



21 



not be increased with enlarged size. The cylindrical portion 
of a long bone is called the shaft, which is hollow for the 
accommodation of the marrow, and also for the purpose of 
obtaining a maximum strength with a minimum weight. 
This principle is well illustrated in iron construction work, 
where supporting columns are made hollow. 

6. Histology of Bone. — If a thin section of bone be exam- 
ined under the microscope, we discover that it is pierced by 





numerous fine tubes, about 
which layers of bone-sub- 
stance are arranged. Fig- 
ure 3 gives a good idea of 
this microscopic structure 
of a human long bone. 
The Haversian canals (a), 
named in honor of their 
discoverer, carry blood; 
the tiny radiating lines 
represent the canaliculi (<•) 
(little canals), which carry blood and lymph to the lacunas (b) 



Fig. 4. — Section parallel to the Surface from 
tiih Shaft of the Femur.- Magnified 10U 
Diameters, a. Haversian canals ; b, e, Lacunae 



2. Experiment. — Obtain one of the long bones of the sheep or calf, 
scrape it thoroughly clean, but do not detach the cartilage covering the 
ends. Saw it through eross^Yis^' in the middle ; then saw the upper halt 
through lengthwise. (See Fig. 1 . ) 



0. What are the Haversian canals ? Canaliculi? Lacuna?? 



22 THE FRAMEWORK OF THE BODY 

(lakes). In each lacuna is a living cell, called a bone-corpuscle. 
These bone-corpuscles feed on nourishment brought to them 
through the canaliculi ; and deposit about themselves layers of 
gelatin and phosphate of lime. These layers are called lamel- 
lae, and make the matrix of the bone. These lamellae are well 
shown in Fig. 3. 

7. Another element of power is found in the curved out- 
line of the bones. The curved line is said to be "the line 
of beauty," as it certainly is the line of strength. It is uni- 
formly present in the bones whose position exposes them to 
accident. The surface of all bones, except the articulating 
surfaces at the ends, is covered by a tough membrane, called 
periosteum. This is pierced by numerous openings through 
which pass the blood-vessels which carry the blood to and into 
the bones. 

8. The Skeleton. — The bones in the human body number 
two hundred and six, and when joined together in their proper 
places, form what is termed the skeleton (Fig. 2). The 
skeleton embraces three important cavities. The first of 
these, surmounting the frame, is a box of bones, called the 
skull; below this is a bony case, or "chest" j and again below 
this, separated only by a thin muscular membrane, called the 
diaphragm, is the abdominal cavity, which ends at the lower 
portion of the trunk in a bony basin called the pelvis. The 
two latter cavities compose the trunk. The trunk and skull 
are maintained in their proper relations by the " spinal 

The transverse section shows the compact, hard outer layer, enclosing 
the soft pulp or marrow. 

The longitudinal section shows, at its upper end, the layer of cartilage, 
its thickness and intimate connection with the bone ; the outer layer of 
bone here is thinnest and gradually increases toward the middle of the 
shaft, where it is thickest ; the central canal, containing the marrow, 
becomes smaller as it approaches the head of the bone, where it is lost in 
the dense network of bony structure. The latter is best demonstrated by 
holding the cut surface for a while under a faucet, so as to wash away the 
blood, etc., contained in the meshes. It will now be seen that these 
meshes are composed o£ delicate, but strong, bony partitions, and 
arranged in such angles to the outer wall and to themselves as will sup- 
port the greatest weight. 

7. Bones, why curved ? 8. What constitutes the skeleton ? 



THE FRAMEWORK OF THE BODY 23 

column." Branching from the trunk are two sets of limbs: 
the arms, which are attached to the chest by means of the 
" collar-bone " and " shoulder-blade " ; and the legs, directly 
joined to the lower part of the trunk. 




Fig. 5. — Eibs in a Natural and Fig. 6. — Eibs showing the Effects 

Healthy State of Tight Lacing 

9. These cavities which we have mentioned are designed 
for the lodgment and protection of the more delicate and 
perishable parts of the system. Thus, the skull, together with 
the bones of the face, shelters the brain and the organs of 
four senses, — sight, hearing, smell, and taste. The chest holds 
the heart, lungs, and great blood-vessels, while the lower part 
of the trunk contains the liver, stomach, and other organs. 

10. The Joints. — The point of union of two or more bones 
forms a joint or articulation, the connection being made in 
various ways according to the kind and amount of motion' 
desired. The movable joints are connected by strong fibrous 
bands, called ligaments. These ligaments are of a silvery 
whiteness, and very unyielding ; so much so, that when sudden 
violence is brought to bear in the vicinity of a joint, the bone 
to which a ligament is attached may be broken, while the 
ligament itself remains uninjured. When this connecting 
material of the joints is strained or lacerated by an accident, a 
"sprain" is the consequence. An injury of this sort may be, 
and frequently is, quite as serious as the breaking of a bone. 

9. What does the skull shelter ? 10. Deseribe the joints. 



24 



THE FRAMEWORK OF THE BODY 



11. The ligament, then, secures firmness to the joint; it 
must also have flexibility and smoothness of motion. This 
is accomplished by a beautiful mechanism, the perfection of 
which is only feebly imitated by the most ingenious contriv- 
ance of man. The ends of the bones are covered by a thin 
layer of cartilage which, being smooth and elastic, renders all 
the movements of the joints very easy, and acts as a cushion. 
Over the cartilage is stretched a thin membrane, making a 





The Ligaments of the Wkist 



Fig. S. — Cells of Cartilage 



compressed closed sack. This is called the synovial mem- 
brane, and is constantly moistened by a colorless liquid, not 
unlike the white of egg in appearance and consistency, whence 
'its name, synovial fluid (synovia = egg-like). 

12. Joints are classified as follows : The ball-and-socket 
joint, which has the greatest freedom of motion, and is exem- 
plified by the hip and shoulder joints ; the hinge joint as shown 
by the elbow ; and the gliding joint, where the motion is pro- 
duced by one surface of bone gliding over another, as shown 
by the wrist and ankle joints. The junction of the first and 
second vertebrae forms a pivot joint, which enables the head to 
be rotated from right to left. The bones of the skull are 
dove-tailed together* by what are termed sutures. 



11. Uses of ligaments and cartilage ? 12. How are joints classified ! 



THE FRAMEWORK OF THE BODY 



25 





Fig. 9. — Elbow- Joint. A, II 



the arm ; B, C. Bones of the forearm 



13. The Spinal Column. — The spinal column is often spoken 
of as " the back bone,'' whereas in reality it is composed 
of twenty-four small bones, called vertebrae. These unite below 
with the sacrum, which forms the base of the pelvis, and upon 
which the weight of the body rests; joined to the lower end 
of the sacrum is a small bone called the coccyx. The vertebrae 
are divided into three groups, of which one contains the seven 
cervical vertebrae, forming the neck, another the twelve dorsal, 
to which the ribs are attached, and the third the five lumbar, 
forming what is called the " small of the back." 

The spinal column is a wonderful piece of mechanism It 
not only connects the important cavities of the body, as has 
already been shown, but also itself forms a canal, which con- 
tains the spinal cord. The joints of the vertebrae are remark- 
able for the thick layers of cartilage which separate the 
adjacent surfaces of bone. The amount of motion between 
any two of these bones is not great; but these little move- 
ments, taken together, admit of very considerable flexibility. 
in several directions, without endangering the supporting 
power of the column. 



13. Describe the spinal column. 



26 



THE FRAMEWORK OF THE BODY 



14. The abundant supply of inter-vertebral cartilage adds 
greatly to the elasticity of the frame. It is due, in part, to 
this elastic material that the brain and other delicate organs 
are not more frequently injured by the shock of sudden 
falls or missteps. During the day, the 
constant pressure upon these joints, 
while the body is erect, diminishes the 
thickness of the cartilages ; so that a 
person is not so tall in the evening as 
in the morning. The effects of this 
compression pass away when the body 
is in a reclining posture. {Read Note 3.) 
15. Cartilage, or "gristle," consists 
of round or oval cells, imbedded in a 
matrix, or base, which varies in the 
three forms of cartilage found in the 
human body. These three are, 1, hya- 
line, 2, white fibro-cartilage, and 3, yellow 
jibro-cartilage. 

Hyaline cartilage is that found on the 
articular ends of bone, and the cartilages 
of the nose and larynx. That covering 
the articular ends of bones serves for 
the purpose of forming bone, the long 
bones receiving their chief growth from 



Sacrui 



Os Coccygis 
Fig. 10 



the cartilages covering both ends. 



■The Spinal 



Column 



White Jibro-cartilage is found, among 
other places, in the disks between the 
vertebrae. It differs from hyaline car- 
tilage chiefly in its matrix, which is 
more fibrous in character. 

Yellow jibro-cartilage differs from the 
white again chiefly in the structure of 
its matrix, whose fibres are found in greater number and 
density. The best example of it is found in the external ear. 

3. Some Causes of Curvature of the Spine. — " Much as horse-riding 
is valued on account of the healthful character of its exercise, yet an over- 
indulgence by young ladies — owing to the oblique position in which the 
14. Value of inter-vertebral cartilage ? Structure? 15. What three forms of cartilage ? 



THE FRAMEWORK OF THE BODY 27 

16. The Growth of Bone. — ■ Bone, like all the other tissues of 
the body, is constantly undergoing change, old material being 
withdrawn, to make room for a fresh supply. This change 
has been shown conclusively by experiments. If an animal be 
fed with madder — a red coloring matter — for a day or two, 
the bones soon become tinged; then, if the madder be discon- 
tinued for a few days, the original color returns. If, however, 
this material be alternately given and withheld, at short inter- 
vals, the bone will be marked by a succession of red and white 
rings. In very young animals, all the bones become colored 
in a single day ; in older ones, a longer time is required. The 
process of waste and repair, therefore, is constantly taking 
place in this hard substance, and with astonishing rapidity. 

17. The Repair of Bone. — Nature's provision for uniting 
broken bones is very complete. At first, blood is poured out 

female form reuts in the side-saddle — will cause the spine to become 
curved." To avoid this, it is important for young ladies to ride occasion- 
ally on the opposite side of the horse. Another frequent cause of curva- 
ture of the spine is the use of the sewing-machine, especially among needy 
seamstresses, whose bread frequently depends on the almost unceasing 
labor of their hands and feet, while sitting in a constrained position. 
Soon after croquet became a favorite amusement among the fashionable 
young ladies of England, it was noticed that the bent position assumed 
during the time the mallet is used, caused a certain deformity, to which 
was given the name of the "croquet curvature." The use of high heels 
on boots and shoes of children, by throwing the weight of the body too far 
forward, on the front of the foot, and destroying the natural poise of the 
body, acts an important part' in causing the spine to become crooked. 
By many this crooked position is considered to be largely a school-room 
disease, for the reason that children often are compelled to sit, and write 
or study, in a bent posture ; but there must be other causes for it, since it 
has been found that it is almost exclusively a female deformity. Over 
eighty-four per cent, of the cases is stated by one writer to be among 
girls. But inasmuch as the majority of these cases begin during the 
years of schooling — from the ages of six to fourteen — great attention 
should be paid to the position of the body during school hours, and ample 
opportunity should be offered, by a regular system of gymnastics, to 
counteract all the evil influences of the school-room posture. — Heather- 
Bigg on Deformities {in part). 



16. Change in bone? Example — animal and madder. Rapidity of change in color? 
Waste and repair ? 

IT. How is a broken bone united ? What becomes of the blood caused by the Injury 1 

What takes its place t How long does it usually take for a broken bone to unite ? 



28 THE FRAMEWORK OF THE BODY 

around the ends of the bone, as a result of the injury. This is 
gradually absorbed, and gives place to a watery fluid, which, 
thickening from day to day, acquires, at the end of about two 
weeks, the consistency of jelly. This continues to harden, by 
the deposit of new bone-substance, until, usually at the end of 
Ave or six weeks, the broken bone may be said to be united. 
It is, however, still fragile, and must be used carefully a 
few weeks longer. The process of hardening continues, but 
months must pass before the union can be said to be complete. 
{Read Note 8.) 

18. Changes in the Skeleton. — Man does not reach his full 
height until he is about twenty-five years old; and even after 
that age, the bones continue to increase in strength and hard- 
ness. Before that age they are comparatively soft and flexible, 
by reason of the gelatin they contain. This is especially true 
in childhood ; and it is fortunate that it is so, since that con- 
dition is much more favorable to the steady and rapid growth 
of the bones than if they contained more of the lime, as is the 
case in old age, when there is no occasion for change in the 
size or shape of the skeleton. The skull, however, is said to 
increase slightly in size, even in advanced life, in those persons 
in whom the brain is continually employed in thought or study. 

4. The Management of a Broken Limb. — "Fractures are usually 
met with when the person is dressed. Therefore, unless there is bleeding, 
or something to call for immediate exposure and examination of the 
damaged part, do not be in a hurry to remove the clothes. If the arm be 
hurt, extemporize a sling from a neck-handkerchief or some other article 
of dress, and support the arm from elbow to wrist, tying the ends of the 
handkerchief in a knot over the coat-collar behind. If the thigh or leg 
be in pain, fasten the injured limb to its fellow by a cravat bandage or 
two, and take care that they lie side by side, and on the same level ; or 
fasten outside the clothes some temporary support — a piece or two of 
straight stick, with a bandage — and then remove the sufferer quietly and 
carefully to some house near at hand. If medical aid be available, send 
for it without any delay ; and be careful, if in the country, and so at some 
distance from the doctor's house, to forward a clear statement as to the 
apparent nature of the accident, which limb is hurt, and where and how 



18. When does a man get his growth ? What changes then take place ? What difference 
in the bones of a child and those of a man ? What exception in case of the skull ? Benefit 
in flexibility of bones ? Cause of knock-knees '! Bow-legs ? 



THE FRAMEWORK OF THE BODY 29 

However, this very flexibility of the bones, in early life, which 
favors their steady growth and prevents their breaking easily, 
is sometimes the source of serious deformity. A young child 
may be allowed to stand and walk too early, and, as a conse- 
quence, the lower limbs become permanently bent inward, in 
the distortion called "knock-knees," or outward, as in "bow- 
legs." For the same reason, a bent position of the spinal 
column, permitted to exist habitually in childhood, may result 
in a life-long deformity. 

19. The Erect Posture. — Youth is, in a great measure, the 
forming as well as the growing period of the frame. Bad 
habits of posture, early formed, become fixed in later life, and 
their results — as seen in contracted chests and round shoulders 
— are with difficulty remedied. Right habits, on the other 
hand, tend to produce an erectness of posture which is favor- 
able, not alone to strength and health, but also to grace and 
ease. The following directions should be learned and prac- 
ticed : hold the head erect with the chin somewhat near the 
neck; expand the chest in front; throw the shoulders back, 
keeping them of the same height on both sides ; maintain the 
natural curves of the spine, as shown in the last figure. Man 
alone, of all the animals, has the power to stand and move in 
the erect posture. 



it happened. Let this statement, too, be in writing, if possible. It may 
well happen, however, that skilled assistance cannot be had, and in this 
case the patient should be undressed quietly and cautiously. It will be 
far better to slit up the dress on the arm or leg with a pair of scissors than 
to pull it off ; but however the covering of the injury may be managed, it 
must be done very slowly and gently, and the limb should be supported 
so as to prevent jarring and shaking to the damaged part. It must be 
carefully kept, too, in a right direction, for otherwise some sharp splinter 
of bone may penetrate the hitherto unwounded skin." — First Help in 
Accidents and Sickness. 



19". What is the forming period? Effects of bad habits of posture? Directions for 
correct posture 1 



30 



THE FRAMEWORK OF THE BODY 



TOPICAL OUTLINE 

1. BONES are composed of mineral substance (lime) two parts, and animal 

substance (gelatin) one part. They are hard on the surface, and light 
and porous in the interior. 
Uses. a. Framework for the body. 

b. Protection for delicate organs. 

c. Levers. 

2. LIGAMENTS. Strong fibrous bands. 

Use. a. Bind bones together. 

3. CARTILAGE. 

Kinds, a. Hyaline. 

b. White fibro-elastic. 

c. Yellow fibro-elastic. 

Uses. a. Forms strong yet flexible frameworks. 

b. Acts as buffers in deadening shocks and blows. 

c. Deepens the sockets of joints ; example, the hip-joint. 

d. Covers the articulating surfaces of bones, thus reducing 

friction. 
C Immovable Sutures, — skull. 



I 
4. JOINTS. \ 

I 



C Gliding joints, — ankle and wrist. 
| Ball-and-socket joints, — shoulder and 
Perfect \ hip. 



Movable. . . \ 



I Hinge joints, — elbow and knee. 
L Pivot joints, — joint of atlas and axis. 
[ Imperfect Vertebrae joints. 



QUESTIONS FOR TOPICAL REVIEW 

PAGE 

1. What useful purposes do the bones serve ? 17. 18 

2. State what you can of the composition of the bones 18, 19 

3. Of the usefulness of lime in the bones 18 

4. Of the usefulness of animal substance in the bones. 19 

5. State what you can of the structure of the bones 19, 21 

6. Of the strength belonging to the bones 21, 22 

7. What is meant by the human skeleton ? 22 

8. Give a description of its construction 23, 24 

9. What is meant by a joint in the human frame ? 23 

10. State what you can of the movable joints 24 

11. What office is performed by the ligaments of the joints ? 24 

12. What by the cartilage at the joints ? 25, 26 

13. What movable joints are there ? 24 

14. Describe the construction of the spinal column 25 

15. What properties and powers does the spinal column possess?.. . . 25 

16. When is a person taller than at other times ? 26 

17. Give the reason for this 26 

18. What can you state of the growth of bone ? 27 

19. Describe the process by which a broken bone is repaired 27, 28 

20. When does man reach his full height ? 28 

21. What changes in the bones then take place ? 28 

22. Name an exception to the general rule 28 

23. State the advantage and disadvantage in flexibility of bones 29 

24. What directions are given for the correct position ? 29 



THE FRAMEWORK OF THE BODY 



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32 



THE MUSCLES 




Fig. 11. —The Muscles 



CHAPTER II 

THE MUSCLES 

The Muscles — Structure — Flexion and Extension — The Tendons — Con- 
traction — Physical Strength — Necessity for Exercise — Its Effects — 
Forms of Exercise — Walking — Riding — Gymnastics — Open-air 
Exercise — Effects of Exercise — Excessive Exercise — Sleep — Rec- 
reation 

1. The Muscles. — The great mass of the body external to 
the skeleton is composed of the flesh, or muscles, which largely 
determine its outline and weight. The muscles are the organs 
of motion. Their number is over five hundred, and to each 
of them is assigned a separate and distinct office. They have 
all been studied, one by one, and a name given to each, by 
the anatomist. They differ in size and shape, each being 
exactly fitted for its peculiar function. Some are very long 
and slender; others are short and thick. (See Fig. 11.) The 
smallest muscles of the human body are those which control 
the bones of the middle ear. Most muscles are attached to 
bones, which they are designed to move or hold in place. 
Such muscles are called skeletal muscles. Others, like the 
muscles of the heart and stomach, are not attached to bones ; 
they carry on the vital processes, and are called visceral 
muscles. 

2. Structure of Skeletal Muscles. — If we examine a piece of 
flesh, we observe that it is soft, and of a deep red color. It 
appears to be composed of layers and bundles of small fibres 
Or fasciculi. The whole muscle is surrounded by a loose sheath 
of connective tissue, called the perimysium. From this main 
sheath partitions extend and envelop eaeli bundle of fibr.es. 



1. What are the muscles? Their Dumber? The design of most o( them? Skeletal 
rhusoles? Visceral muscles? 2. The struoture of flesh J [ts color, etc? Of what is flesh 

composed ? By what is the whole muscle surrounded V 

83 



34 



THE MUSCLES 




Most skeletal muscles taper at one or both, ends until the 
muscular tissue finally disappears, and the sheath gradually 
changes to white, fibrous, inelastic connective tissue which 
forms tendons, by means of which most muscles are attached 
to bone. 

3. When we examine 
these fibres under the mi- 
croscope we discover that 
they in turn are made up 
of still finer fibres, or ji- 
brillce, as shown in Fig. 
12. The fibres are beau- 
tifully marked by par- 
allel wavy lines, about 
ten thousand to an inch, 
which give the fibre its 
name of the striped mus- 
cular fibre. All of the voluntary muscles present this appear- 
ance. 

Striped muscle cells are from one to one and one-half inches 
in length, and from 24 1 00 inch to -%fa inch in breadth. These 
cells lie parallel to each other in bundles. All action of the 
muscles is accomplished by changes in the shape of these cells, 
which act in concert under the control of the nervous system. 

When these cells shorten and thicken, the whole muscle 
undergoes a corresponding change, it contracts ; when the cells 
narrow and lengthen, a similar change occurs in the shape of 
the whole muscle, it relaxes. Each cell is encased in a delicate 
membrane, called sarcolemma, which during life adheres to the 
protoplasm within. Each cell possesses many nuclei which 
lie just under the sarcolemma. Figure 12, a, shows a number of 
these adhering fibrillse; b, shows these bundles torn asunder 
(the sarcolemma is visible at c) ; c, shows how the same cells 
cleave laterally when treated with chemicals such as ammonium 
carbonate. 



Fig. 12. —Muscular Tissue 

a, b, Striped muscular fibres ; c, The same more 
highly magnified 



3. What is the composition of the fibres ? How are the fibres marked ? How long are 
the striped muscle cells ? How broad ? Describe the correspondence between action of the 
muscles and the shape of the cells. 



structure more plainly. 



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STRIPED MUSCLE OF CRAB 

(RELAXED), 

STAINED WITH HEMATOXYLIN, 

TEASED x 250. 

a.— Muscular fibre, or portion of one. 
b. — Fibrils. 




STRIPED MUSCLE OF CRAB 
(EXTENDED), STAINED 
WITH HEMATOXYLIN, 
TEASED x 450. 



A.— Light stripe. 
B.— Dark stripe. 
' C— Intermediate segment in 
light stripe. 




CARDIAC 



MUSCLE (HUMAN), STAINED WITH HEMATOXYLIN x 300. 



JCKiofsam-e, with yellow pigment at poles. 
c— Fibrous tissue between muscle fibres. 
d — Junctions of segments of muscle. 
^_ Capillary blood-vessel. 



THE MUSCLES 35 

4. Structure of Unstriped Muscle. — The visceral muscles, 
except those of the diaphragm and heart, are not arranged 
in definite bundles, nor are they striped. They consist of 
plain, elongated cells which taper toward the ends. These 
cells have the power of shortening in the direction of their 
long axes. But their action is much slower than that of 
striped muscular cells. Unstriped muscles, therefore, con- 
tract with a slow, vermicular (worm-like) motion. Unstriped 
muscles are much lighter in color than striped muscles. 

5. Heart Muscle. — This muscle is dark in color, like skeletal 
muscles. Its action is entirely beyond the control of the will. 
The histology of heart muscle closely resembles that of skeletal 
muscles. Its cells are striped, but they are much smaller than 
the cells of skeletal muscles ; they usually contain only one 
nucleus, and their ends are branched. These branches fit 
closely into one another. 

6. Flexion and Extension. — The muscles are, for the most 
part, so arranged in pairs, or corresponding sets, that when 
motion is produced in one direction by one set, there is, oppo- 
site to it, another muscle, or group of muscles, which brings 
the limb back to its place. When they act alternately, a to- 
and-fro movement results. When a joint is bent, the motion 
is called flexion ; and when it is made straight again, it is 
called extension. When both sets act equally and at the same 




Fig. 13. — Raising the Forearm. A, Biceps muscle 

moment, no motion is produced, but the body or limb is main- 
tained in a fixed position: this occurs when, we stand erect. 

4. How do visceral muscles differ from skeletal muscles? 5, Desoribe the heart muscle. 

0, What is iloxion '! Extension ? 



36 THE MUSCLES 

The muscles which produce extension are more powerful than 
those opposite to them. Muscles which flex are called flexors; 
those which straighten are called extensors. Other muscles 
draw the limbs away from the axis of the body, and are called 
abductors. These are opposed by muscles whose action brings 
the limb back toward the axes of the body ; such are, in con- 
sequence, called adductors. In general, the skeletal muscles 
are paired in the manner just described ; when one contracts, 
its mate must relax, and vice versa. This arrangement is 
commonly called antagonistic. 

7. The muscles are also distinguished as the voluntary and 
involuntary muscles, according as they are, or are not, under 
the control of the will. The heart is an example of the invol- 
untary variety. We cannot change its action in the least by 
an effort of the will. When we sleep, and the will ceases to 
act, the heart continues to beat without cessation. The volun- 
tary muscles, on the other hand, are such as are used only 
when we wish or will to use them — as the muscles of the hand 
or arm (Figs. 13 and 14). {Read Note 1.) 

8. The Tendons. — Tendons, or sinews, are the extremities 
of muscles, and are firmly fastened upon the bone. They are 
very strong, and of a silvery whiteness. They may be felt just 
beneath the skin, in certain parts of the body, when the muscles 
are being used, as at the bend of the elbow ox knee. The 
largest tendon of the body is that which is inserted into 
the heel, called the tendon of Achilles, after the hero of the 
Grecian poet, the fable relating that it was at this point that 
he received his death-wound, no other part of his body being 

1. The Perfection of the Human Hand. — " Gordy counts thirty-four 
distinct movements of the hand, and if we include the combinations of 
these different movements, we shall reach a much higher number. Prop- 
erly speaking, the hand belongs to man alone, and its form does not per- 
mit us to consider it an organ of locomotion, as is the case with certain 
animals most closely resembling man. Nothing gives a more complete 
idea of the perfection of the mechanism of the hand than the execution of 
instrumental music. Examine an artist while he plays the violin. His 
ringers rest upon tfee strings so as to leave them exactly of the length 



T. Describe the voluntary and involuntary muscles, and give examples of each, 8. De- 
scribe the tendons. Mention one. 



THE MUSCLES 



37 





Fig. 14 shows the muscles and tendons of the hand ; A showing the palm, B the back of the 
hand. These numerous muscles and tendons form a very complicated piece of mecha- 
nism, and help to give to the hand its marvellous dexterity and flexibility. Over certain 
joints, such as the wrist and ankle, ligaments in broad bands, as seen in Fig. 14, B, C, 
are bound. They keep the tendons in place. 



vulnerable (Fig. 15). The muscles in the 
front part of the thigh unite to form a sin- 
gle and very powerful tendon, and enclose 
a small bone called the knee-pan, which, 
acting like a pulley, greatly increases 
their power, and at the same time protects 
the front of the knee-joint (Fig. 16). 

9. Muscular Contraction. — The muscles, 
when acted upon by the appropriate stim- 
ulus, contract, or so change their shape, 
that their extremities are brought nearer 
together. The bending of the arm, or of 
a finger, is effected in this manner, by the 
will; but the will is not the only means 
of producing this effect. Electricity, a 
sharp blow over a muscle, and other stim- 
uli, also cause it. Contraction does not 




r nil- LM 



0. What are the causes of muscular contraction ? 



38 



THE MUSCLES 



always cease with life. In man, after death from cholera, 
automatic movements of hands and feet have been observed, 
lasting not less than an hour. In certain cold-blooded animals, 
as the turtle, contraction has been known to take place for 
several days after the head has been cut off. 

10. The property which, in muscle, enables these movements 
to take place is called contractility. If we grasp a muscle while 
in exercise (for example, the large muscle in the front of the 





Fig. 16. — View of Knee-joint. A, Thigh-bone; B, Knee-pan; C, D, Leg-bones 

arm), we notice the alternate swelling and decrease of the 
muscle, as we move the forearm to and fro. It was at one 
time supposed that the muscle actually increased in volume 
during contraction. This, however, is not the case ; for the 



necessary for the tones they are to give. The half of a millimetre, more 
or less, greatly changes the accuracy of the note ; and a chord a milli- 
metre out of place produces a note which even the unpractised ear can 
recognize as false. But the fingers fall upon the strings at precisely the 
point required. They run over them, succeeding each other with giddy 



10. 



What is contractility ? How may the contractility of muscles be seen 



THE MUSCLES 39 

muscle, while gaining in thickness, loses in length in the same 
proportion; and thus the volume remains the same in action 
and at rest. 

11. Contraction is not the permanent, or normal state of a 
muscle. It cannot long remain contracted, but after a time it 
wearies, and is obliged to relax. After a short rest it can then 
again contract. It is for this reason that the heart can beat 
all through life, night and day, by having, as we shall here- 
after see, a brief interval of rest between successive contrac- 
tions. For the same reason, it is more fatiguing to stand for 
any great length of time in one position, than to be walking 
for the same period. Intimately associated with muscular 
tissue in all parts of the body is more or less fat, or adipose 
tissue. It is especially abundant directly under the skin, to 
which it gives an appearance of plumpness and smoothness. 
In prolonged illness, where emaciation is the result, the body 
uses the stored-up fat for nourishment. Fat also gives symme- 
try to the body, serves as cushions, and protects from sudden 
changes of temperature. The histology of adipose tissue shows 
that the fat cells are very simple .in construction. They are 
usually round or oval in shape, possessing a cell wall, enclos- 
ing a globule of fat. The nucleus of the cell from which it 



rapidity, following every imaginable combination, and yet the hand gliding 
over the instrument incessantly changes its position. Sometimes a single 
finger produces an isolated note ; sometimes two or three act simultane- 
ously to produce a concord ; while a fourth, striking a string with increas- 
ing rapidity, produces a trill which rivals the nightingale. Add to all 
these the modifications necessary to swell the sound or let it die away — 
all, in a word, that constitutes musical expression — and it will be admitted 
that this mechanism is allied to the wonderful, and that it surpasses the 
most perfect productions of human art. 1 ' A further idea of the rapidity 
of the hand's movements is given in the playing of a skilful pianist, whose 
hands, oftenest occupied together, produce on an average six to eight 
notes at a time, or about 640 notes in a minute in medium time, and 960 
notes in extremely quick time. — The Wonders of the Human Body. 



11. Is contraction the normal state of the muscle? Can this state be permanently 
maintained? How is the beating of the heart, maintained? Why is it more fatiguing to 
stand for any great length of time in one position, than to be walking for the same period P 
What is adipose tissue? What purposes does it serve? Describe the structure of fat 
cells. 



40 THE MUSCLES 

was developed remains in a flattened form, surrounded by a 
small amount of the original protoplasm at one side of the cell ? 
between the oil globule and the cell wall. 

12. Relative Strength of Animals. — The amount of muscular 
power which different animals can exert, has been tested by 
experiment. By determining the number of pounds which an 
animal can drag upon a level surface, and afterward comparing 
that with its own weight, we can judge of its muscular force. 
It is found that man is able to drag a little less than his own 
weight. A draught-horse can exert a force equal to about 
two-thirds of his weight. The horse, therefore, though much 
heavier than man, is relatively not so powerful. 

13. Insects are remarkable for their power of carrying 
objects larger and heavier than themselves. Many of them 
can drag ten, and even twenty times their weight. Some of 
the beetles have been known to move bodies more than forty 
times their own weight. So far, therefore, from it being a fact 
that animals have strength in proportion to their weight and 
bulk, the reverse of that statement seems to be the law. 

14. Physical Strength. — The difference in strength, as seen 
in different individuals, is not due to any original difference in 
their muscles. Nature gives essentially the same kind and 
amount of muscles to every healthy person, and the power of 
one, or the weakness of another, arises, in great part, from the 
manner in which these organs are used or disused. 

15. Many authors complain of the physical degeneracy of 
men at the present day, as compared with past generations. 
There is room for doubt as to the correctness of this statement. 
Certain experiments have recently been made with the metallic 
armor worn seven hundred years ago, by which it is found that 
any man, of ordinary height and muscular development, can 
carry the armor and wield the weapons of an age supposed to 

12. Muscular power of animals ? How tested? Man's power? Horse's? The com- 
parison ? 

13. Power of insects? Beetles? Give the conclusion. 

14. Difference in strength of individuals ? How caused ? 

15. Complaint in relation to degeneracy? How true? How determined by armor? 
The fair supposition. 



THE MUSCLES 41 

be greatly our superior in strength. When we consider that in 
those days only very strong men could endure the hardships of 
soldier-life, it is fair to suppose that our age has not so greatly 
degenerated in respect to physical strength. 

16. Importance of Exercise. — Action is the law of the living 
body. Every organ demands use to preserve it in full vigor, 
and to obtain from it its best services. The value of that 
training of the mind, which we call education, is everywhere 
recognized. The child is early put to school, and for many 
years continues to study, in order that his brain, which is the 
great centre of mental power, may act healthfully and power- 
fully. It is important that the muscles, also, should receive 
their education by exercise. This is true, not only in respect 
to children, but also of adults whose occupation confines them 
within doors, and requires chiefly brain-work. 

17. Persons who are engaged in manual labor in the open 
air obtain all the exercise necessary for bodily health in their 
regular business : their need is more likely to be a discipline 
or exercise of the mind. A perfect business of life, therefore, 
would be one which would combine both physical and mental 
labor in their proper proportions. If such a business were 
possible for all the human race, life would thereby be vastly 
prolonged. Such, in fact, is to a large extent the occupation 
pertaining to one period of life — childhood. One part of the 
time is given to study, and another to muscular education by 
means of games and sports. The restlessness and playfulness 
of children is not only natural but beneficial. 

18. The Effects of Exercise. — Exercise consists in a well- 
regulated use of the voluntary muscular system. The effects, 
however, are not limited to the parts used. Other organs, 
which are not under the control of the will, are indirectly 
influenced by it. The heart beats more rapidly, the skin arts 
more freely, the temperature rises, the brain is invigorated, 

16. Action ? Use of organs ? Training of the mind ? The child's brain ? Education 
of the body ? 

17. Work, in the open air ? A perfect business 1 The consequence of universal perfeot 
business ? Occupation of children ? 

IS. In what does exercise oonsist ? Effects of it ? 



42 THE MUSCLES 

and the appetite and power of digestion are increased. An 
increased exhalation from the lungs and skin purifies the cur- 
rent of the circulation, and the body as a whole thrives under 
its influence. {Bead Note 2.) 

19. The first effects of exercise, however, are upon the 
muscles themselves ; for by use they become rounded out and 
firm, and increase in power. If we examine a muscle thus 
improved by exercise, we find that its fibres have become 
larger and more closely blended together, that its color is of a 
darker red, and that the supply of blood-vessels has increased. 
Without exercise the muscle appears thin, flabby, and pale. 
On the other hand, excessive exercise, without sufficient relax- 
ation, produces in the muscle a condition not very different 
from that which follows disuse. The muscle is worn out 
faster than nature builds it up, and it becomes flabby, pale, 
and weak. 

20. Violent exercise is not beneficial ; and spasmodic efforts 
to increase the muscular strength are not calculated to secure 
such a result. Strength is the result of a gradual growth, and 
is most surely acquired if the exercise be carried to a point 
short of fatigue, and after an adequate interval of rest. To 
gain the most beneficial results, the exercise should be at regu- 



2. Health in Athletic Exercise. — "Health is perpetual youth — that 
is, a state of positive health. Merely negative health, the mere keeping 
out of the hospital for a number of years, is not health. Health is to feel 
the body a luxury, as every vigorous child does ; as the bird does when 
it shoots and quivers through the air, not flying for the sake of the goal, 
but for the sake of flight ; as the dog does when he scours madly across 
the meadows, or plunges into the muddy blissfulness of the stream ; but 
neither bird, nor dog, nor child enjoys his cup of physical happiness — 
let the dull or the worldly say what they will — with a felicity so cordial 
as the educated palate of conscious manhood. To ' feel one's life in every 
limb,' this is the secret bliss of which all forms of athletic exercise are 
merely varying disguises ; and it is absurd to say that we cannot possess 
this when character is mature, but only when it is half developed. As 
the flower is better than the bud, so should the fruit be better than the 
flower." 

19. General effect upon the muscles ? Special effect ? Effects of inaction ? Of excessive 
exercise ? 

20. Of violent and spasmodic efforts ? Strength, how attained ? Give the particulars. 



Note.— In some cases illustrations of tissue from the lower animals are given for 
the reason that, while the tissue is the same as that of man, the microscope reveals the 
structure more plainly. 



§ 



\/y 



< 



**Y 



A 



f 

NON-STRIPED MUSCLE CELLS, STAINED WITH HEMATOXYLIN. 

a. — Dissociated cells from intestine of cat x 300. 

b. — Muscle cells of external muscular coat of intestine of cat x 300. 

c. — Middle part of isolated cell, under a higher power. 




BLADDER OF SALAMANDER, STAINED WITH HEMATOXYLIN 
AND EOSIN x 300. 
a. — Non-striped muscle cells. 
b.~ Tri-radiate coll. 

ered corpuscles. 
d.— Connective tissue cell of bladder v 



THE MUSCLES 43 

lar hours and during a regular period, the activity and the time 
varying with the strength of the individual, and carefully 
measured by it. {Read Note 3.) 

21. Different Modes of Exercise. — There are very few who 
have not the power to walk. There is required for it no 
expensive apparatus, nor does it demand a period of prelimi- 
nary training. Walking may be called the universal exercise. 
With certain foreign nations, the English especially, it is a 
very popular exercise, and is practised habitually by almost 
every class of society ; by the wealthy who have carriages, as 
well as by those who have none ; by women as well as by men. 

22. Eunning, leaping, and certain other more rapid and 
violent movements are the forms of exercise that are most 
enjoyed in childhood. For the child, they are not too severe, 
but they may be so prolonged as to become injurious. Instances 
have been recorded where sudden death has resulted after 
violent playing, from overtaxing the heart: for example, we 
have the case of a young girl who, while skipping the rope, 

3. The Ill-effects of Over-exertion. — "It should be recollected that 
the action of the muscles has limits, as well as that of every other organ 
of the body. The muscles and the heart may be taxed too severely, and 
permanent derangements may be produced by overtaxing the human 
body. The ancient gymnasts among the Greeks are said to have become 
prematurely old, and the clowns (or acrobats) and athletes of our own 
days suffer from the severe strain put upon their muscular systems." The 
effects of boat-racing in England have been thus described by Dr. Skey, 
an eminent surgeon: "The men look utterly exhausted. Their white 
and sunken features and pallid lips show serious congestion of the heart 
and lungs, and the air of weakness and lassitude makes it a marvel how 
such great exertion should have been so nobly undergone. We have 
repeatedly seen the after ill-effects — spitting of blood, congested lungs, 
and weakness of the heart from over-distension." " Persons should 
neither walk, run, leap, or play at any game, to the extent of producing 
permanent or painful exhaustion. All exercise should be attended with 
pleasurable feelings ; and when pain is produced by proper exercise, those 
who suffer should rather seek medical advice than persevere in exercise." 
— Lankester's Manual of Health. 



21. What may walking be called ? What further Is said of walking ? 

22. What is said of running, and other like movements ? What, as related to childhood ? 
What instances are alluded to ? Example * 



44 THE MUSCLES 

and endeavoring to excel her playmates by jumping the great- 
est number of times, fell dead from rupture of the heart. 

23. Carriage-riding is particularly well suited to invalids 
and persons advanced in life. Horseback exercise brings into 
use a greater number of muscles than any other one exercise, 
and with it there is an exhilaration of feeling which refreshes 
the mind at the same time. It is one of the manliest of exer- 
cises, but not less suitable for women than "for men. To be 
skilful in riding, it should be begun in youth. 

24. For those who live neai streams or bodies of water, 
there are the delightful recreations of boating, swimming, and 
skating. Certain of these exercises have a practical importance 
aside from and above their use in increasing the physical vigor. 
This is especially true of boating and swimming, since they are 
often the means of saving life. Practice in these exercises 
also teaches self-reliance, courage, and presence of mind. 
Persons who have become proficient in these vigorous exercises 
are generally the ones who, in times of danger, are the quickest 
to act and the most certain to do so with judgment. 

25. Physical Culture. — That form of exercise which interests 
and excites the mind, will yield the best results ; but to some 
persons no kind of exertion whatever is, at first, agreeable. 
They should, nevertheless, make a trial of some exercise, in 
the expectation that, as they become proficient in it, it will 
become more pleasant. In exercise, as many sets of muscles 
should be employed as possible, open-air exercise being the 
best. Parlor gymnastics and the discipline of the gymnasium 
are desirable, but they should not be the sole reliance for 
physical culture. No in-door exercise, however excellent in 
itself, can' fill the place of hearty and vigorous activity in the 
open air. (Read Xute 4.) 

4. Exercise should be Pleasurable. — " The world seldom attaches 
much value to things which are plain and easily understood. The dervish 
in the Eastern allegory, well aware of this weakness, knew that it would 
be in vain to recommend the sultan, for the cure of his disease, simply to 



23. Carriage-riding- ? Horseback-riding ? 

24. Boating, swimming, and skating ? 

25. What kind of exercise yields the best results ? What advice is given ? 



THE MUSCLES 45 

26. Excessive Exercises. — If neglect of exercise is injurious, 
so also is the* excess of it. Violent exertions do harm ; they 
often cause undue strain, and even lasting injury to some part 
of the body. For this reason the spirit of rivalry which leads 
to tests of endurance and feats of strength should be dis- 
couraged. Those trials of the muscles, especially, which are 
supposed to demand "training," should not be encouraged. 
Training, it is true, can produce a remarkable muscular develop- 
ment, so that nearly every muscle of the limbs is as large and 
corded as the arm of a blacksmith ; but it is too often at the 
expense of some internal, vital organ. Large muscles are not 
a certain index of good health. It was well known by the 
ancients that athletes of their day were short-lived, notwith- 
standing the perfection, of the physical training then employed. 
When a person overtasks the heart, or, in other words, " gets 
out of breath," he should regard it as a signal to take rest. It 
is well known that both horses and men, after having been 
brought into " condition " for competitive trials, soon lose the 
advantages of their training after the occasion for it has 
passed. 

27. Gymnastic Exercises for Schools and Colleges. — In the 

system of education among the ancients, physical culture pre- 
dominated. In ancient Greece, physical exercises in schools 
were prescribed and regulated by law, and hence these schools 
were called gymnasia. At the present time, on the contrary, 
this culture is almost wholly unknown, as a part of the course 
of education, in our schools, and but to a limited extent in 

take exercise. He knew that mankind in general required to be cheated, 
gulled, cajoled, even into doing; that which is to benefit themselves. He 
did not, therefore, tell the sultan, who consulted him, to take exercise, but 
he said to him: ' Here is a ball, which I have stuffed with certain rare, 
costly, and precious medicinal herbs. Your highness must take this bat, 
and with it beat about this ball until you perspire very freely. You must 
do this every day.' His highness did so, and in a short time the exercise 
of playing at bat and ball with the dervish cured his malady." — First //< Ip. 



26. Physical culture among the ancients ? In Greece? In schools and oolleges at tin 
present time ? Result to the body and mind ? 

27. The result of gymnastics in our colleges and other institutions of learning ? 



46 THE MUSCLES 

colleges. In a few of our schools, however, physical exercises 
have been introduced, with manifest advantage to the students, 
and they form a part of the regular curriculum of exercises, — 
as much so as the recitations in geography, grammar, or Greek. 
The good effect of the experiments, as shown in improved 
scholarship as well as increased bodily vigor, in the institutions 
where the plan has been tried, will, it is hoped, lead to its 
universal adoption. We should then hear less frequently of 
parents being obliged to withdraw their children from school, 
because they become exhausted or, perchance, have lost their 
health from intense and protracted mental application. 

28. Were gymnastics more common in our educational insti- 
tutions, we should not so often witness the sad spectacle of 
young men and women leaving our colleges and seminaries, 
with finished educations it may be, but with constitutions so 
impaired that the life which should be devoted to the accom- 
plishment of noble purposes must be spent in search of health. 
Spinal curvatures, which, according to the experience of phy- 
sicians, are now extremely frequent, especially among women, 
would give place to the steady gait and erect carriage which 
God designed his human creatures should maintain. (Bead 
Notes 5 and 6. ) 

5. Health and Strength are not always Identical. — " Health and 
strength are not synonymous terms. A person may have great strength 
in his limbs, or in certain muscles about the body, but really not have 
good health. It is altogether a mistaken idea to suppose that physical 
exercises have for their sole object the attainment of strength. There 
are other tissues and organs in the human system besides the muscular ; 
and the healthy action of the lungs and the stomach is far more important 
than great strength in the arms, legs, or. the back. It is here, in this 
general exercise of all the muscles and parts of the body, that a well- 
regulated system of gymnastics has its great excellence. It aims to pro- 
duce just that development of the human system upon which good health- 
is permanently based, described by a distinguished writer as follows : — 
1 Health is the uniform and regular performance of all the functions of 
the body, arising from the harmonious action of all its parts, ' — a physical 
condition implying that all are sound, well-fitting, and well-matched. 
Some minds do not look far enough into life to see this distinction, or to 
value it if seen ; they fix their eyes longingly upon strength — upon strength 



5. Were gymnastics more common ? To what are spinal curvatures due ? 



THE MUSCLES 47 

29. All the exercises necessary for the proper development 
of the body may be obtained from the use of a few simple con- 
trivances, that every one can have at home at little cost — less 
by far than that of useless toys. Many of these may be made 
available in the parlor or chamber, though all exercises are far 
more useful in the open air. A small portion of the day thus 
spent will afford agreeable recreation, as well as useful exer- 
cise. The Indian club, the wand, the ring, and the light 
wooden dumb-bell are among the articles devised to assist in 
the smooth performance of class drill. Pleasant music timed 
to the movements of the drill is a further aid, just as martial 
music by a good band is a great help to soldiers on the march. 

30. Home Gymnastics. — This is perhaps a better name than 
parlor gymnastics for those exercises which may be practised 
by individuals at home. Apparatus of various forms, and 
generally simple in construction, has been devised, and may be 
had at small cost. It can be set up in almost any room in the 
house. In some of these appliances cords or bands of rubber 
and pulleys are used; in others, simply weights with cords 

now, and seemingly care not for the power to work long, to work well, 
to work successfully hereafter, which is health." — Dr. Nathan Allen on 
Physical Culture. 

6. On Recreation. — " Our whole method of amusements, especially for 
the young, should be reformed. Gas-light should yield to daylight, night 
vapors in heated and close rooms should give way to fresh air under the 
open heavens, and our young people should be brought up to work and 
play under the ministry of that great solar force which is the most benign 
and god-like agent known to men. Ardent spirits and tobacco should be 
given up, and in their stead genial exercise of riding, gymnastics, and 
the dance, with music and all beautiful arts, should be employed to stir 
the languid powers and soothe the troubled affections. The old Greeks 
taught music and gymnastics as parts of education, and Plato, in urging 
the importance of these, still maintains that the soul is superior to the 
body, and religion is the crown of all true culture. Why may not Chris- 
tian people take as broad a position on higher ground, and with a generous 
and genial culture associate a faith that is no dreamy sentiment or ideal 
abstraction, but the best power of man and the supreme grace of God." 
— Mev. Dr. Osgood on " The Skeleton in Modern Society." 



29. Proper exercise at home ? How obtained at home ? What as to regularity ? 
80. What kind of apparatus is recommended for home gymnastics? Why f Describe 
advantages of the "chest weight." 



48 



THE MCSCLES 



and pulleys, without elastic material. The latter kind is 
better, inasmuch as the movement is even and the action of 

the muscle steady, while with 
rubber bands the farther they are 
stretched the greater is the exer- 
tion. No apparatus yet invented 
answers its purpose so well as the 
"chest weight" (see Fig. 17). By 
its use all the prominent muscles 
of the body are easily exercised. 
No instruction is necessary and 
the space occupied is easily 
spared. A person is obliged only 
to grasp the handles and then 
follow the simple directions given 
to bring into action whatever 
muscles or groups of muscles he 
wishes to exercise. The weight 
can be changed to suit the 
strength of the one exercising. 
Illustrations showing a few of 
the positions and movements that are recommended with one 
of the chest weights, are given in the Appendix, page 367. 




Fig. IT. —The "Chest Weight" 



31. In addition to the movements mentioned many others 
might be employed, varying with the particular muscles or 
parts that require to be exercised. Combinations of cords and 
pulleys suitable for particular cases can be made, and the 
resistance of the weights adjusted to the needs of the weakly 
and the young, as well as to the most robust. These exercises 
are by no means limited to those who are in health and who 
resort to them as a relaxation from long study or sedentary 
occupations. Persons who are not strong, who cannot take 
advantage of school drill, or who are convalescing from sick- 
ness, may, under suitable conditions, be especially benefited by 
them. Not all the movements should be tried at first, but, on 
the contrary, there should be a careful selection of two or 
three that seem to be best suited to the needs of the patient. 

31. Describe some exercises with the "chest weight." 



THE MUSCLES 49 

These exercises must also be undertaken gradually and in- 
creased in proportion to the ability of each individual. There 
should be some degree of uniformity as to the time of day 
as well as to the form and duration of the gymnastic effort 
engaged in. Kemember always to stop short of the point 
where manifest fatigue begins to be felt, regardless of the 
shortness or the length of the time. The keynote to beneficial 
home exercise is to put into use as many muscles as is proper 
and safe, without bringing about a feeling of exhaustion. If 
exhaustion is produced, the exercise passes into violence, and 
as we have formerly learned, violence is harmful. It must be 
remembered that these movements not only develop the parts 
named, but each movement exercises many other muscles at 
the same time. In Figs. 9 and 10 (App.) always take a deep 
breath before each motion. Then the pressure of the filled 
lungs, together with the action of the muscles, will more 
quickly widen and deepen the thorax. 

32. Rest. — We cannot always be active : after labor we 
must rest. We obtain this rest partly by suspending all exer- 
tion, as in sleep, and partly by a change of employment. It 
is said that Alfred the Great recommended that each day 
should be divided in the following manner : " Eight hours for 
work, eight hours for recreation, and eight hours for sleep." 
This division of time is as good as any that could now be 
made, if it be borne in mind that, when the work is physical, 
the time of recreation should be devoted to the improvement 
of the mind; and when mental, we should then recreate by 
means of physical exercise. 

33. During sleep, all voluntary activity ceases, the rapidity 
of the circulation and breathing diminishes, and the tempera- 
ture of the body falls one or two degrees. In consequence, the 
body needs warmer coverings than during the hours of wake- 
fulness. During sleep, the body seems wholly at rest, and the 
mind is also inactive, if we except those involuntary mental 

82. Need of repose? How do we obtain rest? Alfred the Great? The eight hour 
division of time ? 

38. Cessation of voluntary activity ? Temperature of the body ? Consequence! Body 
and mind during sleep J Nutrition V Describe it. Consequence of Insufficient sleep J 



50 THE MUSCLES 

wanderings which we call dreams. Nevertheless a very active 
and important physical process is going on. Nutrition, or the 
nourishing of the tissues, now takes place. While the body is 
in action, the process of pulling down predominates, but in 
sleep, that of building up takes place more actively. In this 
way we are refreshed each night, and prepared for the work 
and pleasures of another day. If sleep is insufficient, the 
effects are seen in the lassitude and weakness which follow. 
Wakefulness is very frequently the forerunner of insanity, 
especially among those who perform excessive mental labor. 

34. All persons do not require the same amount of sleep, but 
the average of men need from seven to nine hours. There are 
well-authenticated cases where individuals have remained with- 
out sleep for many days without apparent injury. Frederick 
the Great required only five hours of sleep daily, and Bonaparte 
could pass days with only a few hours of rest. But this long- 
continued absence of sleep is attended with danger. After 
loss of sleep for a long period, in some instances, stupor has 
come on so profoundly, that there has been no awaking. 

35. There are instances related of sailors falling asleep on 
the gun-deck of their ships while in action. On the retreat 
from Moscow, the French soldiers would fall asleep on the 
march, and could only be aroused by the cry, " The Cossacks 
are coming ! " Tortured persons are said to have slept upon 
the rack in the intervals of their torture. In early life, while 
engaged in a laborious country practice, the writer not unfre- 
quently slept soundly on horseback. These instances, and 
others, show the imperative demand which nature makes for 
rest in sleep. 

36. Alcohol and Strength. — Alcohol, a substance to be fully 
described in our subsequent chapter on Food and Drink, merits 
consideration at this point by reason of the mistaken views 
held by many as to its beneficial effects upon the muscles, 

84. Amount of sleep for different persons ? Cases ? Frederick the Great ? Bonaparte ? 
Instances of long deprivation of sleep ? 

85. Instances of sailors ? French soldiers ? During torture ? 
36. The former use of grog. 



THE MUSCLES 51 

when they are put into vigorous use, and especially into daily 
manual labor. It is well known that for generations it was 
thought to be essential to every army and navy of the civilized 
world that "grog" — which contains alcohol — should be regu- 
larly issued to the hard-worked soldier and sailor, especially 
when they were in the actual service of war. To the slaves, 
also, on many plantations, during the days of slavery in this 
country, a daily ration of rum was given out in the busy 
seasons, in the belief that thus better results, in regard to the 
amount of muscular labor, were secured. So, too, in nearly 
every walk of life where hard muscular labor was demanded, 
a similar belief and practice commonly prevailed, and some 
form of alcohol was resorted to as a trusty servant whenever 
any great or unusual amount of labor was to be called forth. 

37. How Alcohol affects the Muscles. — The scientific progress 
of recent years, however, has put the question in a different 
light, and it is now the commonly received view of scientific 
men that the benefits to labor derived from alcohol were ap- 
parent and not real. Alcohol adds nothing to our bodily 
energy ; it may spur up the muscles to a temporary and extra- 
ordinary exertion, but it does not strengthen the muscles any 
more than does the whip or the spur, that is applied to a hard- 
laboring horse to make him go faster, add to his strength. 

38. Experiments have been made with instruments con- 
structed for the purpose, and the results carefully recorded, 
and these show that a less degree of muscular power is pos- 
sessed by the same person when he is under the influence of 
alcohol than when he has not taken it (see foot-note on p. 241). 
This is no secret to men who go into training to bring about 
the best possible development of their muscular strength; men 
who intend to engage in contests, such as boat-racing, foot- 
racing, and a great variety of other athletic sports, arc taught 
to abstain entirely from all forms of drink that contain alcohol 
if they would bring their powers to the highest point. The 
endurance of severe and prolonged bodily labor is not favored 

37. Present belief as to its use ? 

88. What experiments luvc l> een tried? Training of athletes ? What experience of 

soldiers ? 



52 THE MUSCLES 

by the use of alcohol. The test recently made upon the British 
troops during the Avar in the Soudan, showed that the exhaust- 
ing work, privation, and the burning heat of the desert can be 
better endured by those who have not, than by those who have 
the ration of grog. The time is coming when this ration will 
be a thing of the past, and that, too, for good scientific reasons. 

39. Abnormal Movements due to Alcohol. — The amount of 
disturbance in the muscular system that is produced by alcohol 
varies greatly under different circumstances. It may be very 
great or very slight according as a great or small dose of liquor 
is taken. The tongue, the organ of speech, is a muscle that 
early betrays the presence of drink. This is the cause of what 
is called the " thick " speech of the drunken man, whose words 
are not correctly uttered but are dropped, cut short or run 
together in an unusual and oftentimes unintelligible manner. 
" Seeing double " is another muscular disturbance observed in 
drunkenness. At a certain stage of the drunken fit every 
single object appears to the victim to be double. In this case 
the muscles that move the eyeballs are at fault; they are 
temporarily deranged, so that the two eyeballs cease to move 
harmoniously and are no longer brought to bear upon the 
objects before them, as in health, and the images of two objects 
are reported to the brain, while in reality there is only one. 
Then, too, objects that are at rest appear to be in motion, 
because the eyeballs are affected by an unsteady, rolling 
motion. This is one reason why, at a certain stage, the 
drunken man who tries to walk abroad, begins to stagger from 
side to side over the sidewalk, to stumble and perhaps to fall, 
and sober men appear to him to stagger and be drunk. The 
muscles of his limbs also, in their turn, becoming weakened, 
or not being properly controlled, may refuse to sustain the for- 
lorn pedestrian, and he may be seen clinging for support to 
some friendly lamp-post, or, later on, sinking powerless into 
the gutter. 

39. Does alcohol derange the muscles ? What effect upon the tongue ? The eyes and 
limbs? 



THE MUSCLES 



53 



I. SKELETAL. { 



{ VOLUNTARY 
' MUSCLE. 
(Striated or 



{ Striped.) 



TOPICAL OUTLINE 

Under the control of the will. 

Composed of bundles of fibres. 

These bundles composed of smaller 
bundles {fasciculi), visible to the 
unaided eye, and surrounded by 
sheaths. 

Fasciculi composed of fibres. Average 
diameter about S J 5 in. 

Fibres made up of minute fbrillse 
{fibrils). 

Fibrillae composed of disk-like bodies, 
and consequently striated trans- 
versely. 

Grouped bi-laterally and in pairs. 

Attached to bones by tendons or di- 
rectly. 

( Not under the control of the ivill. 

Found chiefly in the muscular walls 
J of the internal organs and vessels. 
j Fibres composed of elongated cells 
with pointed ends, not marked trans- 
{ versely. 

f Involuntary, yet striped or striated. 
| Striated longitudinally as well as 
! transversely. 

j Fibres composed of oblong and 
[ branched cells. 

III. USES — motion; shape, protection; hold bones in place. 

IV. HYGIENE — nourishment from blood ; exercise : rest ; effects of alcohol 

on strength ; endurance, structure. 

TABLE OF THE PRINCIPAL MUSCLES 
(See Figure 11, Page 32) 



II. VISCERAL, -j 



f INVOLUNTARY 
MUSCLE. 
(Non-striated or 
Unstriped.) 



MUSCLES OF 
THE HEART. 



The Head 

Oc-cip'i-to— fron-ta'lis, moves the scalp and eyebrows. 

Or-bic-u-la'ris pal'pe-brae, closes the eye. 

Le-va'tor pal'pe-brae, opens the eye. 

The Recti muscles (four in number) move the eyeball. 

Tem'po-ral, / ,. , 

Mas-se'ter M raise the lower ]aw. 



The Neck 



Pla-tys'ma My-oi'des, 
Ster'no Mas'toid, 
Sca-le'ni muscles mov< 



move the head forwards. 
the neck from side \o sidt 



54 THE MUSCLES 



The Trunk 

Pec-to-ra'lis, moves the arm forwards. 

La-tis'si-mus dor'si, moves the arm backwards. 

Tra-pe'zi-us, ^ 

Ser-ra'tus mag'nus, >• move shoulder-blade. 

Rhom-boi-de'us, J 

In-ter-cos'tals, move the ribs in respiration. 

External Oblique, j ,, , , . , 

t j. i Avr move the trunk forwards. 

Internal Oblique, J 

E-rect'or spi'nae, move the trunk backwards. 

The Upper Limb 

Del'toid, raises the arm. 

Te'res ma'jor, lowers the arm. 

Sub-scap-u-la'ris, j rotate the arm . 

Spi-na tus, ) 

Bi'ceps, bends forearm. 

Tri'ceps, straightens forearm. 

Pro-na'tor, j rQtate forearm . 

Su-pi-na tor, ) 

Flexor car'pi ra-di-a'lis, 1 

Flex'or car'pi ul-na'ris, I m0Ye the hand# 

Ex-tensor car'pi ra-di-a'lis, 

Ex-ten sor car'pi ul-na'ris, J 

More than thirty muscles take part in moving the fingers. 

The Lower Limb 

Il-i'a-cus, 

Pso'as mag'nus, ,, ., . , t , 

~ , ' r move the thigh forwards. 

Pec-tm-e us, i & 

Ad-duc'tor, J 

It u- e us, move the thigh backwards. 

Pyr-i-form is, ) 

Sar-to'ri-us (from Sa?°'to?\ a tailor), crosses one thigh over the other. 

Rec'tus, / move the j f orw ards. 

Vas tus, ) 

Bi ceps, move the leg backwards. 
Grac l-hs, ) ° 

Tib-i-a'lis, 

Per-o-ne'us ^ move the foot. 

Gas-troc-ne mi-us, j 
So-le'us, J 

Twenty muscles take part in moving the toes. 



QUESTIONS FOR TOPICAL REVIEW 

PAGE 

1. "What can you state of the number and division of the muscles ? 33 

2. Describe the structure of the muscles 33, 34 

3. Their arrangement in pairs and consequent action 35 



THE MUSCLES 55 



PAGE 

4. What is the difference between the motion called flexion and that 

called extension ? 35 

5. Describe their action, and state which are the more powerful 36 

6. What is the difference between voluntary and involuntary muscles ? 36 

7. Illustrate the difference between the two 36 

8. State all you can of the tendons or sinews , 36, 37 

9. What is meant by contraction of the muscles ? 37 

10. In how many and what ways may contraction be effected 38 

11. What is stated of after-death contraction ? 38 

12. Why cannot a muscle in life continue contracted a long time? 38 

13. How then can the constant beating of the heart be explained ? 39 

14. How does the strength of a man compare with that of a horse ? 40 

15. What can you state in regard to the relative strength of animals ? . . 40 

16. What, in relation to physical strength ? «. 40 

17. What, in relation to physical degeneracy ? 40, 41 

18. What, in relation to the importance of exercise ? 41 

19. What is the effect of exercise upon the heart, skin, and appetite? . . 41, 42 

20. How does exercise affect the current of the body's circulation ? 42 

21. How does judicious exercise affect the muscles ? 42 

22. What is stated of violent and spasmodic exercise ? 42 

23. Of the exercise of walking ? 43 

24. Of running, leaping, and other modes of exercise ? 43, 44 

25. Of physical culture, in connection with out-door exercises ? 44 

26. What are the results of excessive exercise ? 45 

27. Of the importance of gymnastics in our schools and colleges ? 45, 46 

28. Of the importance of rest from labor or exercise ? 49 

29. What processes take place during sleep ? 49 

30. What about the amount of sleep required ? 50 

31. What effects follow insufficient sleep ? 50 

32. Illustrate nature's demand for sleep 50 



CHAPTER III 

THE INTEGUMENT, OR SKIN 

The Integument — Its Structure — The Nails and Hair — The Complex- 
ion — The Sebaceous Glands — The Perspiratory Glands — Perspiration 
and Its Uses — Importance of Bathing — Different Kinds of Baths — 
Manner of Bathing — The Benefits of the Sun — Importance of Warm 
Clothing — Poisonous Cosmetics 

1. The Skin. — The skin is the outer covering of the body. 
The parts directly beneath it are very sensitive, and without 
its protection life would be an agony, as is shown whenever by 
accident the skin is broken or torn off, the bared surface being 
very tender, and sensitive even to exposure to the air. Nature 
has provided the body with a garment that is soft, pliable, 
close-fitting, and very thin ; and yet sufficiently strong to ena- 
ble us to come in contact with the objects that surround us, 
without inconvenience or suffering. 

2. The Structure of the Skin. — When examined under the 
microscope, the skin is found to be made up of two layers — 
the outer and the inner. The inner one is called the cutis, or 
true skin; the outer one is the epidermis, or scarf-skin. The 
latter is also known as the cuticle. These two layers are closely 
united, but they may be separated from each other. This sepa- 
ration takes place whenever, from a burn or other cause, a 
blister is formed ; a watery fluid is poured out between the 
two layers, and lifts the epidermis from the true skin. Of the 
two layers, the cuticle is the thinner in most parts of the body, 
and has the appearance of a whitish membrane. It is tough 

1. What is the skin ? Parts directly beneath ? What is shown ? 

•2. Microscopic examination ? What is the cutis ? The cuticle ? Their union ? How 
separated ? What further is said of the cuticle ? 

56 



THE INTEGUMENT, OR SKIN 57 

and elastic, is without feeling, and does not bleed when cut. 
Examine it more closely, and we observe that it is composed 
of minute flat cells, closely compacted, and arranged layer 
upon layer. 

3. The outer layer, the epidermis, is constantly being worn 
out, and falls from the body in the form of very fine scales. 
The scales are dead cells, which are loosened, either singly or 
in groups. Sometimes large portions of the epidermis are thus 
removed. In the scalp such portions are called dandruff. The 
parts which roll up on the skin when it is thoroughly moist- 
ened by perspiration or the bath are from the epidermis. The 
"peeling" of scarlet fever comes from the same source. But 
the epidermis does not wear out. It is constantly renewed 
from the surface of the cutis. Here new, delicate, round cells 
are constantly being formed, each new layer crowding its pred- 
ecessors nearer the surface. Where the surface of the body 
is most subject to friction, as in the palm of the hand and 
soles of the feet, new cells form most rapidly, and consequently 
the epidermis becomes exceptionally hard and thick. 

4. The cutis, or true skin, lies beneath the epidermis, and is 
its origin and support. It is firm, elastic, very sensitive, and 
is freely supplied with blood-vessels. Hence, a needle entering 
it not only produces pain, but draws blood. It is closely 
connected with the tissues below it, but may be separated by 
means of a sharp instrument. The surface of the cutis is not 

1, The Renewal of the Cuticle. — The skin is not a permanent sheath, 
but is, as it were, always wearing out and rubbing oft", and new skin is 
always rising up from underneath. A snake leaves off his whole skin at 
once, as we leave off a suit of clothes or a dress, and sometimes we may 
find his whole cast-off covering turned inside out, just as he crept out of 
it. In man, generally, we do not notice the dead particles of the skin as 
it wears off ; but where the cuticle is pretty thick, as on the soles o\' the 
feet, we can see it peel off in little rolls whenever we wash the feet in hot 
water. After scarlet fever, too, sometimes the dead skin comes o\'i in 
great flakes, and from the hands almost like the fingers of a glove. 
— Bevners. 

■I Wearing out of the cuticle ? What then ? Variety in thickness of cuticle 5 How 

accounted for? 

4. Location and office of the cutis ? What further is said of it ? Papilla 1 To 



58 



THE INTEGUMENT, OR SKIN 



smooth, but covered here and there with minute elevations, 
called papillai. These are arranged in rows, or ridges, such as 
those which mark the palm and thumb ; their number is about 
80 to the square line (a line being one-twelfth of an inch). 
These papillae contain blood-vessels and nerves also, and are 
largely concerned in the sense of touch ; hence they are 
abundant where the touch is most delicate, as at the ends 
of the fingers. The skin is fastened to the underlying tissues 
by a loose elastic (areolar) tissue. This contains fat during 
youth and middle life. The gradual absorption of this fat as 

old age approaches gives the 
a skin a wrinkled appearance. 

This layer is called the sub- 
cutaneous layer. 

5. The Nails and Hair. — 

These are modified forms of 
the cuticle. The nail grows 
from a fold of the cuticle at 
the root, and from the under 
surface. As fast as it is 



formed, it is constantly being 
pushed outward.* The rapidity 
of its growth can be ascertained 
by filing a slight groove on its 

a.b. The Root of a Hair highly magnified sur f a ce, and noticing how the 

^•^"r^L 4 - Se ' s p^ e bet - ee " " a » d the root 

of the nail increases, in the 

course of a few weeks. When the nail is removed by an 

accident, it will be replaced by a new one, if the root be 
not injured. (Notes 2 and 6.) 




Fig. 18 



*The practice of biting the nails should be avoided not only because 
of the ugly shape which is produced, but because it impairs the sense of 
touch in the ends of the fingers. In paring the nails, let them remain long 
enough nearly to cover the pulp of the finger. Avoid scraping either sur- 
face of the nail ; do not injure the " quick." 

2. The Life of the Cells of the Body. — " The life of the body is long 



5. What are the nails and hair ? 
Accident to the nail ? 



The growth of the nail ? The rapidity of its growth 



THE INTEGUMENT, OR SKIN 59 

6. The hairs are produced in a similar manner; the skin 
forming depressions, or hair-sacs, from the bottom of which 
they grow and are nourished (Fig. 18). They are found, of 
greater or less length, on almost all parts of the surface, except 
the palms of the hands and soles of the feet. On certain parts 
of the body, they grow to great length ; on other parts they 
are so short, that they do not rise beyond the hair-sac from 
which they grow. 

7. The bulb, or root, from which the hair arises, is lodged 
in a small pouch, or depression of the skin. The shaft is the 
part which grows out beyond the level of the skin. Its growth 
is altogether in one direction, in length alone. The outer part 
of the hair is quite firm, while its interior is softer, and supplies 
the nutriment by which it grows. The hair is more glossy in 
health than at other times. 

8. The nail serves as a protection to the end of the finger, 
and also enables us to grasp more firmly, and to pick up small 
objects. The hair, too, is a protection to the parts it covers. 
On the head, it shields the brain from extremes of heat and 
cold, and moderates the force of blows upon the scalp. On 
the body, it is useful in affording a more extensive surface for 
carrying off the perspiration. 

under fortunate circumstances ; that of our cells is short. We all know 
that the surface of the body is covered by layers of cells. The super- 
ficial layers are in loose connection ; they are cells in old age. The fric- 
tion of our clothing daily removes an immense number of them. A 
cleanly person who uses sponge and towel energetically every day rubs off 
a still greater quantity. 

" We swallow ; our tongue acts in speaking ; drink and food pass this 
way. Now, the mucous membrane of the mouth is covered with layers 
of cells. Here, also, many thousand senile cells are rubbed off daily. 
And so on through the entire digestive tract. An immense number of 
cells— these living corner-stones of the body — is thus lost daily. 

"To show the duration of life in one kind of cell, let as turn to the 
human nail. The latter, growing from a furrow of the skin, is made up 
of skin-cells. In the depth of the furrow, youth prevails ; at the upper 
margin — which we trim — old age. Berthold proved that a nail-cell 



6. How are the hairs produced ? Difference in their length ? 

7. Root of the hair? Shaft? Firmness and softness of the hair I 

8. Office of the nail 1 Of the hair ? Give tho illustrations. 



GO 



THE INTEGUMENT, OR SKIN 



9. Complexion. — In the deeper cells of the cuticle lies a 
pigment, or coloring-matter, consisting of minute colored grains. 
On this pigment complexion depends ; and its presence, in less 
or greater amount, occasions the difference of hue that exists 
between the light and the dark races of men, and between the 
blonde and the brunette of the white races. Freckles are due 
to an irregular increase of this coloring matter. 

10. The sun has a powerful influence over the development 
of this pigment, as is shown by the swarthy hue of those of 
the white race who have colonized in tropical climates. It is 

also well illustrated by the fact, 
that among the Jews who have 
settled in northern Europe, 
there are many who are fair- 
complexioned, while those re- 
siding in India are as dark as 
the Hindoos around them. 

11. An Albino is a person 
who may be said to have no 
complexion ; that is, there is 
an entire absence of coloring 
matter from the skin, hair, and 
iris of the eye. This condition 
exists from birth, and more 
frequently occurs among the 
dark races, and in hot climates, 
although it has been observed in almost every race and clime. 

12. Sebaceous Glands. — In all parts of the surface where 
the hairs grow, are to be found the sebaceous, or oil-producing 




Fig. 19. — Showing a Hate and Sectio 
of Skin Highly Magnified 



lives four months in summer and five in winter. A person dying in his 
80th year, has changed his nail 200 times, at least — and the nail appeared 
such an inanimate, unvarying thing ! No other cells, we believe, have a 
life nearly so long as that of the nail." — Compendium of Histology by 
Heinrich Frey. 

9. On what does the complexion depend ? Light and dark races ? Freckles ? t 

10. Influence of the sun ? How illustrated ? Jews ? 

11. What is an Alhino ? Where are Albinos found '? 

12. What are sebaceous glands ? How do they act ? Sebaceous glands of the face ? 
How do they act ? 



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THE INTEGUMENT, OR SKIN 



61 



glands. These glands are little rounded sacs, usually connected 
with, the hair-bulbs; and upon these bulbs they empty their 
product of oil, which acts as a natural dressing for the hair 
(Fig. 18). A portion of the sebaceous matter passes ont upon 
the surface, and prevents the cuticle from becoming dry and 
hard. The glands situated upon the face and forehead open 
directly upon the skin. In these, the sebaceous matter is 
liable to collect, and become too hard to flow off naturally. 

13. These glands on the face and forehead frequently appear 
on the faces of the young as small, black points, which are 
incorrectly called " worms." It is true, that 
occasionally living animalcules are found in 
this thickened sebaceous matter, but they can 
only be detected by the aid of the micro- 
scope. This sebaceous matter acts not only 
to keep the skin flexible, and furnish for 
the hair an oily dressing, but it especially 
serves to protect the skin and hair from the 
acridity arising from the perspiration. 

14. The Perspiratory Glands. — The chief 
product of the skin's action is the perspira- 
tion. For the formation of this, there are 
furnished countless numbers of little sweat- 
glands in the true skin. They consist of fine 
tubes, with globe-like coils at their deeper 

extremity. Their mouths or openings may 

J ■ , l & J Fig. 20. — Magnified 

be seen with an ordinary magnifying-glass, view of a Sweat- 
upon the fine ridges which mark the fingers. g^ D ' WITH "™ 
These tubes, if uncoiled, measure about one- a, the plana surrounded 
tenth of an inch in length. In diameter pL^nT^rough^the 
they are about one three-hundredth of an dermis ; c, its continu- 

. ation through the rete 

inch, and upon parts of the body there are mucosum, and ,/. 
not far from three thousand of these glands " mm r h th0 u w> er l ' 1 " 

1 dermis 

to the square inch. Their whole number in 

the body is, therefore, very great; and it is computed, if they 




18. Black points, called worms : J Animalcules ? Service performed by sebaceous matter 
14. Perspiration '? Sweat glands ? Of what do they consist? Dimension of the tubes ; 



62 THE INTEGUMENT, OR SKIN 

were all united, end to end, their combined measurement would 
exceed three miles. 

15. The Sensible and Insensible Perspiration. — The pores of 
the skin are constantly exhaling a watery fluid; but, under 
ordinary circumstances, there is no moisture apparent upon 
the surface, for it evaporates as rapidly as it is formed. This 
is called insensible perspiration. Under the influence of heat 
or exercise, however, this fluid is formed more abundantly, 
and appears on the surface in minute, colorless drops. It is 
then termed sensible perspiration. 

16. Water is the chief component of this fluid, there being 
about ninety-eight parts of water to two parts of solid matter. 
The quantity escaping from the body varies greatly, according 
to the temperature of the air, the occupation of the individual, 
and other circumstances. The average daily amount of per- 
spiration in the adult is not far from two pints, or more than 
nine grains each minute. 

17. The Uses of the Perspiration. — Besides liberating from 
the blood this large amount of water, with the worn-out matter 
it contains, the perspiration serves to regulate the temperature 
of the body. That is to say, as evaporation always diminishes 
temperature, so the perspiration, as it passes off in the form 
of fine vapor, cools the surface. Accordingly, in hot weather 
this function is much more active, and the cooling influence 
increases in proportion. When the air is already charged with 
moisture, and does not readily receive the vapor of the body, 
the heat of the atmosphere apparently increases, and the 
discomfort therefrom is relatively greater. 

18. The importance of perspiration is shown by the effects 
that often follow its temporary interruption, namely, headache, 
fever, and the other symptoms that accompany " taking cold." 
When the perspiration is completely checked, the consequences 

15. What is sensible perspiration ? Insensible perspiration ? 

16. Components of perspiration ? Upon what does perspiration depend ? Amount of 
perspiration daily ? 

17. What does perspiration set free from the blood ? What other service does perspira- 
tion perform ? Explain the process. 

18. Effect of interruption of excretion ? What experiments are mentioned ? 



THE INTEGUMENT, OR SKIN 63 

are very serious. Experiments have been performed upon 
certain smaller animals, as rabbits, to ascertain the result of 
closing the pores of the skin. When they are covered by a 
coating of varnish impervious to water and gases, death ensues 
in from six to twelve hours — the attendant symptoms resem- 
bling those of suffocation. {Bead Note 3.) 

19. It is related that, at the coronation of one of the Popes, 
about three hundred years ago, a little boy was chosen to act 
the part of an angel ; and, in order that his appearance might 
be as gorgeous as possible, he was covered from head to foot 
with a coating of gold-foil. He was soon taken sick, and 
although every known means were employed for his recovery, 
except the removal of his fatal golden covering, he died in a 
few hours. # 



3. On Taking Cold. — "Of all the things to which humanity is liable, 
there is none which recurs more frequently, and whose consequences are 
more troublesome and often dangerous, than ' taking cold.' Some persons 
have quite a faculty for taking cold, while others do so but rarely. And 
yet the one does not argue delicacy of constitution, or the other strength. 
The body of man has a constant and agreeable temperature in health, the 
variation being slight. In fact, any great variation is incompatible with 
health, and constitutes disease. Clothes, by preventing the radiation 
away of heat from the surface, retain it, and so the feeling of cold is not 
so great — that is, the surface does not become so cold. Clothes are non- 
conductors'of heat when dry ; but let them be saturated with water, and 
unless the loss of heat be met by increased production, there is a lowering 
of the body temperature — 'taking cold.' Thus, if exertion be continued, 
and more heat is produced to meet the loss until a change of dry clothing 
is procurable, no injury results. But let the wet clothes be worn without 
a corresponding heat production, as when children sit down in school in 
their wet clothes, or the shop-boy stands in his moist garments ; then 
there is a rapid loss of heat, a lowering of the body temperature, and a 
cold is ' caught.' So is a cold caught by wet feet, when the heat is radi- 
ated away from the feet; if exercise be continued the cold is not experi- 
enced. A damp bed gives cold because the moist bedclothes conduct 
away the heat, and the body temperature is lowered." — Fothergill on the 
Maintenance of Health. 

* A clogged action of the skin is disastrous in many diseases, but 
especially those attended by an eruption, or "breaking out." One of 
these — small-pox — is exceeding fatal among the American Indians, whole 
tribes having been swept away by it. And this is explained by the fact 



19. Give the story ia rolatiou to the boy covered with gokM'oil. 



64 THE INTEGUMENT, OR SKIN 

20. The Importance of Bathing. — From these considerations, 
it is evident that health must greatly depend upon keeping the 
skin clean. "He who keeps the skin ruddy and soft, shuts 
many gates against disease." For as the watery portion of the 
perspiration evaporates, the solid matter is left behind. There, 
also, remain the scales of the worn-out cuticle, and the excess 
of sebaceous matter. In order to secure the natural action of 
the skin, these impurities require to be removed by the fre- 
quent application of water. {Bead Note 4. ) 

21. In warm climates, and during hot weather, bathing is 
especially necessary. For a person in good health, a daily 
cold bath is advisable. To this should be added occasionally 
a warm bath, with soap, water alone not being sufficient to 
remove impurities of a greasy nature. Soap facilitates this, 
by forming with such substances a chemical mixture, which is 
taken up by water, and by it removed from the body. {Bead 
Note 5.) 

that they habitually close their pores by covering their bodies with bears' 
grease, as a protection against the cold, and with earthy paints as a means 
of decoration. 

4. Bathing. — "When the civilization of Egypt, Greece, and Rome 
faded, the world passed through dark ages of mental and physical bar- 
barism. For a thousand years there was not a man or woman in Europe 
that ever took a bath, if the historian of those times, Michelet, is to be 
believed. No wonder that there came the wondrous epidemics of the 
middle ages, which cut off one-fourth of the population of Europe — the 
spotted plague, the black death, sweating sickness, and the terrible mental 
epidemics which followed in their train — the dancing mania, the mewing 
mania, and the biting mania. Not only their persons, but their houses 
were uncleanly, even in the classes that were well-to-do. Filth, instead 
of being abhorred, was almost sanctified." — Lyon Playfair. 

5. An Imaginary Conversation on Baths and Bathing. — "I have 
often amused myself, by fancying one question which an old Roman 
emperor would ask, were he to rise from his grave and visit the sights of 
London under the guidance of some minister of state. The august shade 
would, doubtless, admire our railroads and bridges, our cathedrals and 
our public parks, and much more of which we need not be ashamed. 
But after a while, I think, he would look round, whether in London, or 
in most of our great cities, inquiringly and in vain, for one class of build - 



20. Give the quotation. Perspiration ? 

21. Ablution in warm climates ? What advice is given ? 



THE INTEGUMENT, OR SKIN 65 

22. There is a maxim by the chemist Liebig, to the effect, 
that the civilization of a nation is high, in proportion to the 
amount of soap that it consumes ; and that it is low, in propor- 
tion to its use of perfumes. In some degree, we may apply 
the same test to the refinement of an individual. The soap 
removes impurity; the perfume covers, while retaining it. 
{Bead Notes 6 and 7.) 

ings, which in his empire were wont to be most conspicuous and splendid. 
'And where,' he would ask, ' are your public baths ? ' And if the min- 
ister of state who was his guide should answer — ' O great Caesar, I really 
do not know. I believe there are some somewhere in some out-of-the-way 
place ; and I think there have been some meetings lately, and an amateur 
concert, for restoring, by private subscriptions, some baths and wash- 
houses which had fallen to decay. And there may "be two or three more 
about the metropolis ; for parishes have power to establish such places, if 
they think fit, and choose to pay for them out of the rates : ' — Then, I 
think, the august shade might well make answer — ' We used to call you, 
in old Rome, northern barbarians. It seems that you have not lost all 
your barbarian habits. Are you aware that, in every city in the Roman 
empire, there were, as a matter of course, public baths open, not only to 
the poorest freeman, but to the slave, usually for the payment of the 
smallest current coin, and often gratuitously ? Are you aware that in 
Rome itself, millionaire after millionaire, emperor after emperor, built 
baths, and yet more baths ; and connected with them gymnasia for exer- 
cise, libraries, and porticoes, wherein the people might have shade and 
shelter, and rest ? Are you aware that these baths were of the most 
magnificent architecture, decorated with marbles, paintings, sculptures, 
fountains, what not ? And yet I had heard, in Hades down below, that 
you prided yourselves here on the study of the learned languages.' " — 
Bev. Charles Kingsley on the Air-mothers. 

6. Care of the Skin and Nails. — " Much ignorance prevails amongst 
the public as to the use of soap and water. Those who have very sensitive 
skins should use soft water, for the face at all events, and the best water, 
if it can be had, is rain-water with the cold taken off it. Nor is it every 
kind of soap which is tolerated by such persons ; probably the safest soaps 
are, not those which are said to contain, but those which really do contain, 
a large portion of glycerin. 

"The culture of the nails, which when perfect constitute so great a 
beauty, is of much importance ; but the tendency is to injure them by too 
much attention. The scissors should never be used, except to pare the 
free edges when they have become ragged or too long, and the folds of 
scarf skin which overlap the roots should not, as a rule, be touched. The 
upper surfaces of the nails should on no account be touched with the knife, 



22. Liobig's maxim ? What further Is added ? 



23. The Different Kinds of Baths. — All persons are not alike 
able to use the cold bath. When the health is vigorous, a 
prompt reaction and glow upon the surface will show that it is 
beneficial. Where this pleasurable feeling is not experienced, 
but rather a chill and sense of weakness follows, we are warned 
that the system will not, with impunity, endure cold bathing. 
Most persons experience the best results when the water is 
about the temperature of the body — "blood-heat." 

24. It should also be borne in mind, that the warm or hot 
bath cannot be continued so long, or repeated so frequently, as 
the cold, on account of the enervating effect of unusual heat so 
applied to the body. For persons who are not in robust health, 
one warm bath each, week is sufficient. Such persons should 
be careful to avoid every extreme in reference to bathing, 
clothing, and whatever greatly affects the action of the skin. 

25. Sea-bathing is even more invigorating than fresh-water 
bathing. Those who cannot endure the fresh water, are often 
benefited by the salt-water baths. This may be accounted for, 
in part, by the stimulant action upon, the surface, of the saline 
particles of the sea-water ; but the exciting scenes and circum- 
stances of sea-bathing also exert an important influence. The 
open-air exercise, the rolling surf, the genial weather, and 
usually the cheerful company, add to its intrinsic benefits. 
(Bead Note 8.) 

as it is so often done, the nail brush being amply sufficient to keep them 
clean, without impairing their smooth and polished surfaces." — People's 
Magazine. 

7. On Scents. — " They are the only resource of rude and dirty times 
against offensive emanations from decaying animal and vegetable sub- 
stances, from undrained and untidy dwellings, from unclean clothes, from 
ill-washed skins, and from ill-used stomachs. The scented handkerchief, 
in these circumstances, takes the place of the sponge and the bath ; the 
pastile hides the want of ventilation ; the otto of roses seems to render 
the scavenger unnecessary ; and a sprinkling of musk sets all other smells 
and stinks at defiance." — Johnston. 

8. The Proper Use of Sea-bathing. — "The length of time during 
which a person should remain in the water necessarily varies according to 



23. What is said about cold bathing ? 

24. What is said about warm bathing ? 

25. What is said about sea-bathing ? 



THE INTEGUMENT, OR SKIN 67 

26. Time and Manner of Bathing. — A person in sound health 
may take a bath at almost any time, except directly after a full 
meal. The most appropriate time is about three hours after a 
meal, the noon-hour being probably the best. For the cold 
bath, taken rapidly, no time is better than immediately after 
rising. Those beginning the use of cold baths should first try 
them at 70° Fahrenheit, and gradually use those of a lower 
temperature. From five to twenty minutes may be considered 
the proper limit of time to remain in a bath ; but a sensation 
of chilliness is a signal to withdraw instantly, whether at 
home, or at the sea-side. Two sea-baths may be taken daily ; 
one of any other kind is sufficient. 

27. The body should be warm, rather than cold, when step- 
ping into the bath ; and after it, the skin should be thoroughly 
dried with a coarse towel. It is best to continue friction until 
there is a sensation of warmth or " glow " throughout the entire 
surface. This reaction is the test of the good effects of the 
bath. If reaction is still incomplete, a short walk may be 
taken, especially in the sunshine. It is very congenial, how- 

the age, sex, and constitutional strength of the bather. Due regard should 
also be had to the state of the weather and season of the year. 

"In the case of children, five, gradually extended to ten minutes ; of 
women, ten to fifteen minutes ; and of men, a quarter of an hour or more, 
is a fair average period. There are some people, doubtless, to whom 
these periods will appear insufficient, and who insist on remaining so long 
in the water that their skin becomes cold and blue, their teeth begin to 
chatter, and a condition of general exhaustion comes on ; people, in short, 
who have the ' most ' for their money, like the countryman who grumbled 
at having been conveyed thirty miles in about half-an-hour by an express 
train, on the score that the length of time occupied in the journey was 
not proportionate to the fare that he had paid. On entering the water, 
the bather should immerse the whole of the body two or three times, so 
as to get the action of the shock from the cold water distributed over its 
entire surface. There should be no hesitancy, no dabbling about with 
the feet, but a good plunge at once into the next wave that washes in. 
Upon coming out of the water the bather should dry the body with good 
rough towels, dress quickly, and take a brisk walk for a short distance. 
If there be any feeling of exhaustion or nervous depression, a little food 
or drink should bo taken." 



20. What Is said .as to tho time and manner of bathing ? 

27, Condition of tho body when bathing t Direction, after bathing ? 



68 

ever, both, to health and comfort, to rest for a short time 
directly after bathing, or to take some light refreshment. 
This is better than severe exercise or a full meal. 

28. Bathing among the Ancients. — The Romans and other 
nations of antiquity made great use of the vapor-bath as a 
means of preserving the health, but more particularly as a 
luxury. Their method was not unlike that employed in some 
parts of Europe at the present day. The public baths of Borne 
and other cities are among the grandest and most interesting 
monuments of ancient luxury and splendor ; and from their 
ruins have been recovered some of the most beautiful works 
of art. 

29. The Thermae, as the baths of Rome were called, were of 
great extent, built very substantially, and ornamented at vast 
expense. They were practically free to all, the cost of a bath 
having been less than a cent. It is related that some persons 
bathed seven times a day. After the bath, their bodies were 
anointed with perfumed oil. If the weather was line, they 
passed directly from the Thermae into the gymnasium, and 
engaged in some gentle exercise previous to taking the midday 
meal. Between two and three in the afternoon was the favor- 
ite hour for this ancient luxury. Swimming was a favorite 
exercise, and a knowledge of it was regarded as necessary to 
every educated man. Their common expression, when speak- 
ing of an ignorant person, was, "He can neither read nor 
swim." 

30. The Sun-Bath. — Some also were accustomed daily to 
anoint themselves, and lie or walk in apartments arranged for 
the purpose, with nake v d bodies exposed to the direct rays of 
the sun. There is an interesting allusion to this practice, in a 
letter of the younger Pliny to the historian Tacitus, describing 
the destruction of Pompeii by an eruption of Vesuvius. " My 
uncle" (Pliny the elder) "was at that time in command of the 
fleet at Misenum. On the 24th of August, about one in the 
afternoon, my mother desired him to notice a cloud which 

28. Bathing among the ancients ? Baths of Rome ? 

29. After the bath ? Swimming among the ancients ? 

30. The sun-bath ? The story of Pliny ? 



THE INTEGUMENT, OR SKIN 69 

seemed of unusual shape and dimensions. He had just returned 
from taking the benefit of the sun, and after a cold bath, and a slight 
repast, had retired to his study.'* Then follows a description 
of the destruction of Pompeii, and the death of the elder Pliny. 

31. We may judge somewhat of the benefits of the sun, by 
observing the unnatural and undeveloped condition of plants 
and animals which are deprived of light. Plants become 
blanched and tender ; the fish of subterranean lakes, where the 
light of day never enters, are undersized, and have no eyes ; 
tadpoles kept in the dark dp not develop into frogs ; men 
growing up in mines are sallow, pale, and deformed. Besides 
the well-known effect of solar light in tanning the skin, it also 
makes it thicker and better able to resist exposure ; though 
the complexion may be thereby injured, the health gained 
more than compensates for the loss of beauty. " To make 
good the loss of the lily, where the sun has cast his ray, he 
seldom fails to plant the rose." (Bead Notes 9 and 10.) 

32. Clothing.^ — In reference to clothing, we are far more 
apt, in our changeful climate, to use too little than too much. 

9. Light Influences Growth and Health. — "I have several times 
taken two potatoes which were as nearly as possible alike, and placed 
one under a bell-glass through which the light could pass, and the other 
under a similar cover rendered opaque by several coats of black paint. 
Sprouting went on unchecked under the translucent glass, while it was 
always notably retarded and sometimes prevented in the potato under the 
dark glass. Milne Edwards, a distinguished French physiologist, per- 
formed a series of experiments which showed that tadpoles when deprived 
of light did not develop into the frog. I have several times repeated his 
experiments, and always with confirmatory results. On one occasion I 
prevented for one hundred and twenty-five days the development of a 
tadpole, by confining it in a vessel to which the rays of light had no 
access. On placing it in a receptacle open to the light, the process of 
transformation was at once begun, and was completed in fifteen days. 
The practical application of these and similar observations is this, that. 
care should be taken both in health and disease to insure a sufficient 
amount of sunlight to the inmates of houses, and that it is impossible to 
rear well-formed, strong, and robust children unless attention is paid to 
this requirement." — Hammond on the Influence of Light. 

* Man is the only animal that requires clothing j and as he advances 



81. Benefit of the sun ? Effect upon plants ? Skin ? 

82. Direction about clothing? Exposing limbs of ohildren? nothing, night and day ? 



70 THE INTEGUMENT, OR SKIN 

Aii aphorism of Boerhaave, worth remembering, if not of 
adopting, is, " We should put off our winter clothing on mid- 
summer's day, and put it on again the day after." He also 
says, " Only fools and beggars suffer from the c.olcl ; the latter 
not being able to get sufficient clothes, the others not having 
the sense to wear them." The practice of exposing the limbs 
and necks of young children, for the alleged purpose of " hard- 
ening " them, is quite hazardous. It is not to be denied that 
some seem to be made tough by the process. But it is so only 
with the rugged children; the delicate ones will invariably 
suffer under this fanciful treatment. As the skin is constantly 
acting, by night as well as by day, it is conducive both to 
cleanliness and comfort to entirely change the clothing on 
retiring for the night. The day-clothing should be . aired dur- 
ing the night, and the bedding should be aired in the morning, 
for the same reason. {Bead Notes 11 and 12.) 

from barbarism to civilization, more and more attention is paid to dress 
as a means of protection against cold. Asa rule, more harm arises from 
using too little clothing than too much, especially in a changeful climate 
like our own. 

10. Light in the Sick-room. — "It is the unqualified result of all my 
experience with the sick, that second only to their need of fresh air is 
their need of light ; that, after a close room, what hurts the in most is a 
dark room; and that it is not only light, but direct sunlight they want. 
You had better carry your patient about after the sun, according to the 
aspect of the rooms, if circumstances permit, than let him linger in a 
room when the sun is off. People think that the effect is upon the spirits 
only. This is by no means the case. Who has not observed the purify- 
ing effect of light, and especially of direct sunlight, upon the air of a 
room ? Here is an observation within everybody's experience. Go into 
a room where the shutters are always shut (in a sick-room or a bed-room 
there should never be shutters shut), and though the room be uninhabited 
— though the air has never been polluted by the breathing of human 
beings, you will observe a close, musty smell of corrupt air — of air 
unpurified by the effect of the sun's rays. The mustiness of dark rooms 
and corners, indeed, is proverbial. The cheerfulness of a room — the 
usefulness of light in treating disease — is all-important. It is a curious 
thing to observe how almost all patients lie with their faces turned to the 
light, exactly as plants always make their way toward the light." — 
Florence Nightingale^ 's Notes on Nursing. 

11. Underclothing and Bedding. — All clothing worn during the day 
should be removed at night. A practice prevails in tropical countries of 
shaking thoroughly every article of apparel just before it is placed on the 



THE INTEGUMENT, OR SKIN 71 

33. Poisonous Cosmetics. — The extensive use of cosmetics for 
the complexion is a fertile source of disease. The majority of 
these preparations contain certain poisonous mineral substances, 
chiefly lead. The skin rapidly absorbs the fine particles of 
lead, and the system experiences the same evil effects that are 
observed among the operatives in lead works and painters, 
namely, "painters' colic," and paralysis of the hands, called 
"wrist-drop." 

body. The motive which prompts this comes from the fear lest a centi- 
pede or other lively and virulent specimen of natural history has hid itself 
somewhere within the folds of the garment. Even without the danger of 
wearing one's shirt in conjunction with such an intruder, it is an excellent 
practice to shake it and every other article of clothing thoroughly before 
putting them on. The garments worn next to the skin should be changed 
before they become saturated with the secretions of the sebaceous glands. 
This can be accomplished by renewing them twice a week, though the 
majority of people only change them once in that period. Combe recom- 
mends to wear two sets of flannels, each being worn and aired by turns, 
on alternate days ; he likewise praises a practice common in Italy, 
namely, instead of beds being made up in the morning the moment they 
are vacated, and while still saturated with the nocturnal exhalations, the 
bed-clothes are thrown over the backs of chairs, the mattresses shaken 
up, and the window thrown open for the greater part of the day. This 
practice, so consonant with reason, imparts a freshness which is peculiarly 
grateful and conducive to sleep. Florence Nightingale, who never fails 
to speak plainly, says: " Feverishness is generally supposed to be a 
symptom of fever ; in nine cases out of ten it is a symptom of bedding. 
A real patient should have two beds, remaining only twelve hours in 
each ; on no account to carry his sheets with him." — Draper (in Part). 

12. Rules as to Clothing. — Protection against Cold. — For equal 
thicknesses, wool is much superior to either cotton or linen, and should 
be worn for all underclothing. In cases of extreme cold, besides wool, 
leather or waterproof clothing is useful. Cotton and linen are nearly 
equal. 

Protection against Heat. — Texture has nothing to do with protection 
from the direct solar rays ; this depends entirely on color. "White is the 
best color; then gray, yellow, pink, blue, black. In hot countries, there- 
fore, white or light-gray clothing should be chosen. In the shade the 
effect of color is not marked. The thickness and the conducting power 
of the material are the conditions (especially the former) which influ- 
ence heat. 

The body should not only be so protected by its covering as to be kept 
from rain and damp, but the clothing must be so ventilated that the 



oo. Cosmetics ? Fuiutors' colic ? 



72 THE INTEGUMENT, OB SKIN 

34. Certain hair-dyes also contain lead, together with other 
noxious and filthy ingredients. These do not work as great 
harm as the cosmetics, since they are purposely kept away 
from the skin; but they rob the hair of its vitality. Eye- 
washes, too, are made from solutions of lead, and many an eye 
has been ruined by their use. They deposit a white metallic 
scale on the surface of the eye, which, when in front, perma- 
nently blurs the sight. 

emanations from the skin shall not accumulate. The wearing of the 
unventilated beaver hat, or fur cap, is a ready method of suppressing 
the natural growth of the hair, and of causing the retention of that effete 
epithelial scale commonly called scurf, or dandruff. The wearing of 
tightly fitting waterproof coats cannot be habitually practiced without 
danger to the wearer ; the very painful and troublesome ailment, rheuma- 
tism, has in many persons been produced by this manner of locking in 
the excretions of the surface. — Dr. B. W. Richardson. 



THE INTEGUMENT, OR SKIN 



73 



Epidermis 



Rete 
Mucosum 



Dermis 



SKIN 



Glands 



Nails 



Hairs 



PERSPIRA- 
TION 



{ Composition 



Quantity 



Uses 



TOPICAL OUTLINE 

Composed of flattened scales. 

Horny and transparent. 

Impermeable to fluids. 

No nerves or blood-vessels. 

Simply protective. 

Surface continually removed by friction. 

Softer and less transparent. 

Contains pigment cells. 

Gives colour to the skin. 

Fibres of connective and elastic tissues. 

Numerous blood-vessels and nerves. 

Drawn up into papillse. 

Fat-cells in deeper portion. 

' Situated deep in the dermis. 
Consist of coiled tubes. 



Sweat 



Surrounded 

WG7%S. 



Ducts 



by capillary net- 

Nearly straight 
through dermis. 

Twisted in epi- 
dermis. 

Open at the sur- 
face {pores). 



I Sebaceous 



Secretion 



L Secrete the perspiration. 
f Connected with hairs, 
j Secrete an oily fluid. 

f Discharged into the 
J follicles. 
I Lubricates the hair 
I and skin. 
Thick, horny plates of epidermis. 

f Only where adherent to skin. 
Growth . . < Above, below, and behind at the 

( root. 
Pushed forward by growth behind. 

[" Interior medullary portion or 
A pith. 

( Outer cortical or fibrous portion. 
( Bulb-like at lower extremity. 
1 Imbedded in follicle, 
j Pushed outward by growth at the base. 
I Glands — sebaceous (see above), 
j Muscles — tend to erect the hair by their coll- 
ie traction, 
f Water. 

! Salts — especially common salt. 
[ Little carbonic acid gas in solution, 
f Average about two pounds a day. 
; Greater in summer than in winter. 



Shaft 



Root 



^ Greater during activity. 

| Removal of waste matter. 

j Tends to reduce the temperature of the body 

[ by its evaporation. 



74 THE INTEGUMENT, OR SKIN 



QUESTIONS FOR TOPICAL REVIEW 

PAGE 

1. What are the characteristics of the skin, and what office does it 

perform ? 56 

2. What can you state of the structure of the skin ? 5(3 

3. Describe the cuticle and tell its use 56, 57 

4. Describe the cutis or true skin and tell its use 57, 58 

5. What can you state of the nature and growth of the nail ? 58 

6. Explain growth of the hair ? 59 

7. Of the nature and growth of the hair ? 59 

8. Of the offices performed by the nails and hair ? 59 

9. What is an Albino ? 60 

10. How is the difference in complexion in different persons accounted 

for ? 60 

11. How is the presence of freckles accounted for? 60 

12. How does Nature provide a dressing for the hair ? 60, 61 

13. What is the composition of perspiration ? 62 

14. What other service do the sebaceous glands perforin ? 61 

15. State what you can of the perspiratory glands and their number?. . 61, 62 
l(i. What is the difference between sensible and insensible perspiration ? 62 

17. State the uses and importance of perspiration ? 62, 63 

18. What impurities gather naturally on the skin ? 64 

19. What are the effects of stopping perspiratory action ?. 62, 63 

20. Repeat what is said of the importance of bathing ? 64, 65 

21. Different kinds of baths for different individuals? 66 

22. When should we indulge in cold, warm, and sea-bathing? 67 

23. What is the effect in each case ? 67 

24. What directions are given as to the time and manner for bathing?. 67 

25. What is related of bathing among the ancients ? 68 

26. Directions after the bath ? 68 

27. What is related to show the antiquity of sun-bathing ? 68, 69 

28. What are the effects of sun-bathing ? 69, 70 

29. What directions are given in relation to clothing the body ? 69, 70 

30. What can you state of poisonous cosmetics ? 71, 72 

31. Of hair-dyes and eye-washes ? 72 



CHAPTER IV 

THE CHEMISTRY OF FOOD 

«The Source of Food — Inorganic Substances — Water — Salt — Lime — 
Iron — Organic Substances — Albumen, Fibrin, and Caseine — The 
Fats or Oils — The Sugars, Starch, and Gum — Stimulating Substances 
— Necessity of a Regulated Diet 

1. The Source of Food. — The term food includes all those 
substances/ whether liquid or solid, which are necessary for 
the nourishment of the body. The original source of all food 
is the earth, which the poet has fitly styled the " Mother of all 
living." In her bosom, and in the atmosphere about her, are 
contained all the elements on which life depends. But man 
is unable to obtain nourishment directly from such crude 
chemical forms as he finds in the inorganic world. They 
must, with a few exceptions, be prepared for his use, by being 
transformed into new and higher combinations, more closely 
resembling the tissues of his own body. 

2. This transformation is effected, first, by the vegetable 
world. But all plants are not alike useful to man, while some 
are absolutely hurtful. Accordingly, he must learn to discrimi- 
nate between that which is poisonous and that which is life- 
supporting. Again, all parts of the same plant or tree are not 
alike beneficial : in some, the fruit; in others, the leaves; and 
in others, the seeds only are sufficiently refined for his use. 
These he must learn to select; he must also learn the proper 
modes of preparing each kind for his table, whether by cooking 
or other processes. {Bead Note 1.) 



1. The Circle of Organic Life. — " Man, as an animal, is chemically an 
oxidizing agent, reducing again to primitive forms the principles built up 



1. The term food ? Source of food ? Need of preparing food ? 

2. Usefulness and hurtfulness of plants : ; Whal then musl man do ? Parts of the same 

plant or tree ? 

75 



76 THE CHEMISTRY OF FOOD 

3. Again, certain forms of the vegetable creation which are 
unfit, in their crude state, for man's food, and which he rejects, 
are chosen as food by some of the lower animals, and are, by 
them, made ready for his use. Thus the bee takes the clover, 
that man cannot eat, and from it collects honey. The cattle 
eat the husks of corn and the dried grass, that are by far too 
coarse for man, and in their own flesh convert them into tissues 
closely resembling his muscular tissue. In this way, by the 
aid of the transforming processes of the vegetable and animal 
creations, the simple chemical elements of the mineral kingdom 
are elaborated into our choice articles of food. {Read Note 2.) 

by the vegetable world, and taken in by him either directly as vegetables, 
or indirectly in the shape of the material of other animals. Without 
vegetable life animals could not exist, and never could have existed ; side 
by side they grow and flourish, indispensable to each other's existence ; 
the tree breaking up the exhaled carbonic acid of the animal — the carbon 
being stored up in its increasing mass — while the oxygen is returned 
again, free and uncombined, to the atmosphere for the respiratory needs 
of the animal world. Round and round go the elementary bodies in 
ceaseless change of form, nevertheless never more than they were at first 
and will be at the last — the atomic material of this planetary sphere 
being ever absolutely the same in amount. The material of the bodies of 
Saul and his sons, when burnt by the men of Israel after their ignominious 
exposure at Bethshan, in consequence of their defeat on Mount Gilboa, 
are circulating amongst us still; it served others before them, and has 
formed part of thousands since. It is quite within the bounds of chemical 
possibility that some of the atoms contained in the fated apple of Eve, 
may have lain in the material of the apple which revealed to Newton the 
law of gravitation." — Fothergill on the Maintenance of Health. 

2. The Food Circle in Nature. — " There are some ultimate elements 
in flesh as in flour, the same in animals as in vegetables. The vegetable 
draws food from the soil and from the air, and being fully matured, it or 
some part of it is eaten by the animal. But in completing the circle, the 
vegetable receives and thrives upon the animal itself, in whole or in part, 
or the refuse which it daily throws off. The very bones of an animal are 
by nature or man made to increase the growth of vegetables and really to 
enter into their structure ; and being again eaten, animals may be said 
to eat their own bones, and live on their own flesh. Hence there is not 
only an unbroken circle in the production of food from different sources, 
but even the same food may be shown to be produced from itself. Surely 
this is an illustration of the fable of the young Phoenix arising from the 
ashes of its parent." — Edward Smith on Foods. 



3. Certain forms of vegetable creation ? Example of the bee ? Cattle ? The inference ? 



THE CHEMISTRY OF FOOD 77 

4. Inorganic Substances. — The substances we use as food 
are classified as organic and inorganic. By organic substances 
are meant those derived from living forms, such as vegetables 
and animals. Inorganic substances are those simpler inani- 
mate forms which belong to the mineral kingdom. The former 
alone are commonly spoken of as food; but the latter enter 
very largely into the constitution of the body, and must there- 
fore be present in our food. With the exception of two articles 
— water and common salt — these substances enter the system 
only when blended with organic substances. 

5. Water. — Water, from a physiological point of view, is 
the most important of all the articles of food. It is every- 
where found in the body, even in the bones and the teeth. It 
has been computed that as large a proportion as two-thirds of 
the body is water. The teeth, the densest of the solids in the 
human system, contain ten per cent, of water. The muscles, 
tendons, and ligaments are more than half water; for it is 
found that they lose more than half their weight when dried 
with moderate heat. But it is in the fluids of the body that 
water is found most abundantly. It gives to them the power 
of holding a great variety of substances in solution, and is the 
great highway by which new supplies are conveyed to the point 
where they are required, and by which old particles of matter, 
that have served their uses, are brought to the outlets of the 
body to be thus removed from the system. {Bead Notes 3 and 4.) 

3. The Only Natural Drink. — " Water is the natural drink of man, 
as it is of all organized beings. It enters more largely into his compo- 
sition than any other substance, giving liquidity to the blood, moisture to 
all the tissues," and serving as the great solvent of the body ; not less 
than two-thirds of its weight being of that element. It seems as if all 
organic beings were so much "organized water." "Soft water is more 
wholesome than hard, though water moderately hard is not perceptibly 
injurious. When very hard, a part of the salts of lime can readily be 
precipitated by boiling. As a rule, spring and well-waters, if brought 
from deep fountains, are better and more wholesome than running 



I. What classification ? Define organic substanoes. Inorganic. Organic, how spoken 
Of? The inorganic ? Water and salt ? 

r>. Water in physiology ? Where found? Computation? Water in the teeth? Mus- 
cles, tendons, ami ligaments F How ascertained ? Water in the fluids of the bodj ? What 

is the advantage ? 



78 THE CHEMISTRY OF FOOD 

6. Man can remain a longer time without solid food than 
without water. He may be deprived of the former for ten or 
twelve hours without great suffering, but deprivation of water 
for the same length of time will produce both severe pain and 
great weakness. The food should contain not less than two 
parts of water to one of solid nutriment. Water constitutes 
the great bulk of all our drinks, and is also a large constituent 
of the meats, vegetables, and fruits which come upon the table. 
Fruits, especially, contain it in great abundance, and, in their 
proper season, furnish most agreeable and refreshing supplies 
of the needed fluid. 

7. Common Salt. — Salt, or sodium chloride, as an article of 
food, is obtained chiefly from the mineral kingdom ; although 
plants contain it in small quantities, and it is also found in the 
tissues of nearly all animals used as food. In the human body 
it is an ingredient of all the solids and fluids. The importance 

streams. Well-water, in towns and cities, unless brought from a great 
depth, is wholly unfit for drinking and cooking. The immense quantity 
of organic matter which permeates every inch of the soil, for many feet in 
depth, precludes the possibility o£ water passing through it without being 
corrupted. Kiver water, polluted by sewers, is as disgusting to the senses 
as it is destructive to health. The notion that impure water can be 
rendered more wholesome by icing it is an erroneous one. Ice-cold 
drinks in summer, while the body is heated, are capable of producing 
lifetime disease, and even instant death." — J. B. Black on the Ten Laws 
of Health. 

4. The Sustaining Power of Water. — " Water is the most reliable 
and grateful drink for man. Nature has many admixtures in the juices 
of fruits, but none so satisfying to excessive thirst as pure water. It will 
even prolong life when nutritious food is not taken, as we have a well- 
known instance, recorded by Dr. McNaughton, in the transactions of the 
Albany Institute of New York for 1836. The case was that of a man 
who lived upon water alone for fifty -three days. This he did while labor- 
ing under some delusion which impelled him to abstain from all ordinary 
nourishment — water alone could he be induced to partake of. His 
strength was tolerably well sustained during the first six weeks ; he was 
able, in fact, to go out of doors ; and even on the day of his death he was 
able to sit up in bed.'" — Dr. James Knight. 



6. Length of time man can do without food or water ? Give the comparison. Bulk of 
drinks ? Constituent of meats, etc. ? Fruits ? 

7. Salt, how obtained? Where found? In the human body? Importance of salt? 
What else can you state of the value of salt ? 



THE CHEMISTRY OF FOOD 79 

of salt to animal life in general, is shown by the great appetite 
for it manifested by domestic animals, and also by the habitual 
resort of herds of wild beasts to the " salt-licks " or springs. 
In those parts of the world where salt is obtained with diffi- 
culty, man places a very high price upon it. 

8. Experiments upon domestic animals show that the with- 
drawal of salt from their food not only makes their hides 
rough and causes the hair to fall out, but also interferes with 
the proper digestion of food. If it be withheld persistently, 
they become entirely unable to appropriate nourishment, and 
die of starvation. {Bead Note 5.) 



5. Of Salt.— 

" Salt-cellars ever should stand at the head 
Of dishes, wheresoe'er a table's spread. 
Salt will all poisons expurgate with haste, 
And to insipid things impart a taste. 
The richest food will be in great default 
Of taste, without a pinch of sav'ry salt. 
Yet of salt meats, the long-protracted use 
Will both our sight and manhood, too, reduce ; 
On tables salt should stand both first and last, 
Since, in its absence, there is no repast." 

— The Code of the School of Salernum. 

"Animals will travel long distances to obtain salt. Men will bar- 
ter gold for it ; indeed, among the Gallas and on the coast of Sierra 
Leone, brothers will sell their sisters, husbands their wives, and parents 
their children for salt. In the district of Accra, on the gold coast of 
Africa, a handful of salt is the most valuable thing upon earth after gold, 
and will purchase a slave or two. Mungo Park tells us that with the 
Mandingoes and Bambaras the use of salt is such a luxury that to say of 
a man, ' he flavors his food with salt,' it is to imply that he is rich ; and 
children will suck a piece of rock-salt as if it were sugar. No stronger 
mark of respect or affection can be shown in Muscovy, than the sending 
of salt from the tables of the rich to their poorer friends. In the hook of 
Leviticus it is expressly commanded as one of the ordinances of Moses, 
that every oblation of meat upon the altar shall be seasoned with salt, 
without lacking ; and hence it is called the Salt of the Covenant of God. 
The Greeks and Romans also used salt in their sacrificial cakes; and it 
is still used in the services of the Latin church — tho 'pawn mien/ or 
pinch of salt, being, in the ceremony of baptism, put into the child's 
mouth, while the priest says, k Receive the salt of wisdom, and may it be 



S. Experiments upon onimalb! 



80 THE CHEMISTRY OF FOOD 

9. Salt is usually taken into the system in sufficient quantities 
in our food. Even the water we drink often has traces of it. 
The habitual use of much salt in cooking, or as a seasoning at 
the table, is not wise ; and while it may not lead to consump- 
tion, as some writers declare, it is a bad habit in itself, and 
leads to the desire for other and more injurious condiments. 

10. Lime. — This is the mineral substance which we have 
spoken of before as entering very largely into the composition 
of the bones. It is the important element which gives solidity 
and permanence to the framework upon which the body is 
built. Calcium tri-phosphate, or "bone-earth," is the chief 
ingredient of the bones and teeth, but is found in the carti- 
lages and other parts of the body in smaller quantities. {Read 
Note 6.) 

a propitiation to thee for eternal life.' Everywhere, and almost always, 
indeed, it has been regarded as emblematical of wisdom, wit, and immor- 
tality. To taste a man's salt, was to be bound by the rites of hospitality , 
and no oath was more solemn than that which was sworn upon bread and 
salt. To sprinkle the meat with salt was to drive away the devil ; and to 
this day, among the superstitious, nothing is more unlucky than to spill 
the salt." — Letheby on Food. 

6. Phosphate of Lime and other Inorganic Substances. — "All food 
contains certain saline substances. If we burn a portion of the flesh of 
any animal, we may drive off the carbon, oxygen, hydrogen, and nitrogen, 
and ' ashes ' are left. These ashes are the saline and mineral (inorganic) 
constituents of the animal. They exist in the blood and tissues, and are 
as essential to the life of the animal as those other elements which were 
expelled by heat. Like the latter, they are constantly being used up and 
carried off from the body, and like 'them must be replaced by means 
of our food. Cooking, especially boiling, tends to dissolve away some of 
these salts, and care should be taken to supply them by means of uncooked 
food, as fresh vegetables and fruits ; milk also contains them. One of 
the most important of these inorganic substances is phosphate of lime, 
or ' bone-earth,' as it is called, from the fact that about forty per cent, of 
healthy bone is made up of it. When it is deficient, the bones are soft 
and are liable to be bent by the actions of the muscles attached to them, 
and a permanent deformity may be the consequence. This form of lime 
is contained in wheat, barley, oats, and rye, and from these sources the 
chief supply of it is derived. These plants require phosphate of lime for 



9. Salt, how taken into the system ? Its use in cooking ? Consumption ? 
10. Lime in the bones ? What does it impart ? Chief ingredient of the bones and teeth ? 
Where else found ? 



THE CHEMISTRY OF FOOD 81 

11. How does this substance find its way into the body ? 
Meat, milk, and other articles obtained from the animal king- 
dom contain it, and it is abundantly stored away also in the 
grains from which our bread is made — in wheat, rye, and 
Indian corn. In early life, while the body is growing, the 
supplies of this substance should be carefully provided. The 
evil effects of the deprivation of it are too often and painfully 
evident in the softening of the bones, and in the predisposition 
to curvature of the spine — deformities which are most deplor- 
able and which continue through life. 

12. Iron. — This substance is probably the most abundant 
and widely diffused of the metals. It is found in most of 
the vegetables, and is a very important component of animal 
tissues. It enters into the composition of human blood in 
about one part per thousand. Ordinarily, the food conveys to 
the system enough iron for its use, but it must sometimes be 
introduced separately as a remedy, especially after great loss 
of blood, or after some wasting disease. Under its influence 
the blood seems to be rapidly restored, and a natural color of 
the lips and skin replaces the pallor caused by disease. 

13. Other Inorganic Substances. — In addition to the sub- 
stances mentioned, the mineral kingdom supplies compounds 
of soda, potash, and magnesia, which are essential for the use 
of the body. They occur in small quantities in the body, and 
enter it in combination with the various articles of diet. 

14. Organic Substances. — These substances are derived from 
the vegetable and animal creations. They comprise all those 

their growth and the perfecting of their grains ; hence it is supplied 
artificially by the farmer. A diet deficient in substances yielding the 
phosphate of lime is injurious to man, and should be avoided. Its 
presence in wheat-flour accounts in part for the fact that our ordinary 
loaf of bread makes so good a 'staff of life,' and that it is, ami has been, 
so widely used as an article of food by the strongest ami most vigorous 
races of mankind. 1 ' — Lankester's Manual. 



It. How does lime find its way into the body ? Early lift ? Effeot of its deprivation P 
1'2. Iron, its abundance and diffusion ? Where found? What part of the blood is it? 
How supplied to the system ? In ease of loss of Mood or wasting disease ' 
18. Soda, potash, and magnesia? How do they ooour? 
14. Organio substances, whence derived ? What do they oomprise ? Groups? 



82 THE CHEMISTRY OF FOOD 

articles which are commonly spoken of as "food," and which. 

are essential to sustain the body in life and strength. They 
are divided into three groups, namely : the Albuminoid sub- 
stances, the Fats, and Sugars. 

15. The Albuminoids. — This class includes three important 
nutritive substances — (1) Albumen, which gives it its name; 
(2) Fibrin, including gluten; and (3) Caseine. These com- 
pounds constitute a large part of the human body, and the 
food contains them in proportionally large quantities. Their 
importance is so great, and the system so promptly suffers 
from their absence, that they have been styled the "nutritious 
substances."' The properties which they hold in common are, 
that they do not crystallize, and have a jelly-like form, except 
when heat is applied to them, when they harden, or coagulate. 

16. They likewise decompose, or putrefy, under the influence 
of warmth and moisture. Hence the decay of all dead animal 
tissues. Cold arrests this process. It is well known that 
milk, eggs, and the like, "keep" much longer in winter than 
at other seasons. The bodies of elephants, caught in the ice 
many hundred years ago, are occasionally borne by the icebergs 
to the coast of Siberia, completely frozen, but preserved almost 
perfectly in form and limb. 

17. Albumen exists in milk, meat, the grains, and the juices 
of many plants ; but the purest form is obtained from the 
white of egg. AYhcn we consider that an egg is composed 
chiefly of albumen and water — namely, six parts in seven ; 
and when we also consider the numerous, diverse, and complex 
tissues — the muscles, bones, internal organs, bill, claws, and 
feathers — with which the chick is equipped on leaving his 
shell, we are impressed with the importance of these apparently 
simple constituents of the food and body. (Bead Xote 7.) 



7. Weight and Health. — '-The weight of the body is very generally 
assumed to be an infallible index or proof of the maintenance of a healthy 



15. The Albuminoid class includes what ? These compounds constitute what ? The 
food ? Their importance ? Their properties ? 

16. Decomposition? Effect of cold ? Illustrations? Elephants? 

17. In what substances does albumen exist ? What further is said of the egg? 



THE CHEMISTRY OF FOOD 83 

18. Fibrin is derived from meats, and exists in the blood 
both of man and the lower animals. Gluten, or vegetable 
fibrin, resembles closely true fibrin, and is abundantly furnished 
in wheat and other grains from which flour is commonly made. 
Animal fibrin coagulates spontaneously when it is removed 
from the body, and thus causes the " clotting " of the blood. 

19. Caseine is the curdy ingredient of the milk, and a highly 
important food-substance. Its coagulation in milk takes place 
not from heat, but by the addition of an acid, and also when 
milk becomes sour from exposure to the air. It is commonly 
effected, however, by introducing a piece of rennet, a prepara- 
tion made from a calf's stomach. The curds, or caseine, may 
then be separated from the ivhey, and made into cheese, by 
pressing it sufficiently to drive off the water. 

20. The Fats or Oils. — This is the second group of organic 
foods. Those which are more solid are called fats; the more 
fluid ones are the oils. Oleaginous substances are supplied in 
both animal and vegetable food; but, from whatever source 
derived, they are chemically much alike. They are insoluble 
in water, and yet they unite readily with the watery fluids of 
the body, and are by them conveyed to its various parts for 
their nourishment. This is due to their property of " emulsi- 
fying ; " that is, they are held in suspension, in a finely divided 
state, in water. Ordinarily milk is an example of an em ulsion. 

condition of the body ; and that food which keeps up the weight has been 
regarded as satisfactory and nutritious. But this is not always a sate 
judgment, owing to the property in water from innutritions food to make 
good the loss of weight caused by the withdrawal of albumen and fat. 
The weight may remain the same, while we are 'losing flesh.' Fat, 
also, may increase in badly nourished people, while the more essential 
element of albumen is diminishing ; the fact being that the badly fed are 
not always lighter than those who are well nourished. And further, the 
feeling of satisfaction after eating is deceptive ; the Irish peasant who 
consumes ten pounds of potatoes in a day feels quite satisfied, but is in 

reality badly nourished by his diet containing three-fourths water." 

Prof. Voit, of Munich. 

18. Fibrin, pluten, clo'.ting of the blood ? 

10. Caseine ? Its coagulation ? Ett'ect of rennet ? Making of cheese ? 
'20. What are the fats ? The oils ? How supplied? How ulifc.o \ Kuiuaufyipi? > Qfc 
ample ? How do we know It ? 



84 THE CHEMISTRY OF FOOD 

We know that it contains fat, for butter is obtained from it ; 
and, under the microscope, the minute oil-globules may be 
distinctly seen. 

21. In our country and climate, and also in colder climates, 
fatty articles of food are principally derived from the animal 
creation, such as meat or flesh, milk and butter. But most of 
the bread-stuffs contain more or less fat or oil — Indian meal 
as much as nine parts in a hundred. 

22. Among persons living in cold climates, the appetite for 
oleaginous food is especially eager ; and they require large 
quantities of it to enable them to resist the depressing influ- 
ences of cold. Since vegetation is scanty and innutritious, and 
the waters of the frozen regions abound in animal life, they 
must rely wholly upon a diet derived from the latter source. 
The Esquimau consumes daily from ten to fifteen pounds of 
meat or blubber, a large proportion of which is fat. The 
Laplander will drink train-oil, and regards tallow-candles as a 
great delicacy. In hot climates, on the contrary, where flourish 
the olive and the palm, this kind of food may be obtained 
from vegetable sources in abundant quantities. {Bead Notes 
Sand 9.) 

8. The Necessity of Fat in the Food of Children. — " Children who 
dislike fat cause much anxiety to parents, for they are almost always thin, 
and, if not diseased, are not healthy. If care be not taken, they fall into 
a scrofulous condition, in which diseased joints, enlarged glands, sore 
eyes, and even consumption occur ; and every effort should be made to 
overcome this dislike. If attention be given to this matter of diet, there 
need be no anxiety about the possibility of increasing the quantity of food 
consumed ; whilst the neglect, the dislike, will probably increase until 
disease is produced. The chief period of growth — viz., from seven to 
sixteen years of age — is the most important in this respect, for a store of 
fat in the body is then essential. Those who are inclined to be fat usually 
like fat in food, and then it may be desirable to limit its use. Some who 
cannot eat it when hot like it when cold, and all should select that kind 
which they prefer. Those living in Kussia and Lapland devour very 
large quantities — as seven pounds daily — and eat it even raw, while 
those dwelling in hot countries use very little. It produces more heat 
than any other kind of food." — Edward Smith on Health. 



21. Whence are fatty articles of food derived ? 

22. Appetite of persons in cold climates ? What do they require ? Upon what must 
they reiy ? Why ? The Esquimau ? Laplander ? Olive and palm ? 



THE CHEMISTRY OF FOOD 85 

23. The Sugars, or the Saccharine Substances. — These con- 
stitute the third and last group of the organic substances which 
are employed as food. This group embraces, in addition to the 
different kinds of Sugar, the varieties of starch and gum, from 
whatever source derived. The two substances last named do 
not, at first sight, present many points of similarity to sugar ; 
but they closely resemble it in respect to their ultimate chem- 
ical composition, being made up of the same elements, in nearly 
the same proportions. And their office in the system is the 
same, since they are all changed into sugar by the processes of 
digestion. 

24. Sugar is chiefly of vegetable origin, the animal varieties 
being obtained from honey and milk. The most noticeable 
characteristic of this substance is its agreeable, sweet taste, 
which makes it everywhere a favorite article of food. But 
this quality of sweetness is not possessed by all the varieties 
of sugar in the same degree; that obtained from milk, for 
instance, has a comparatively feeble taste, but rather imparts 
a gritty feeling to the tongue. The other important properties 

9. The Effect of Climate on the Appetite. — " Climate has an impor- 
tant influence on the quantity of food demanded by the system ; and 
every one has experienced in his own person a considerable difference at 
different seasons of the year. Travelers' accounts of the amount of food 
consumed by the natives of the frigid zone are almost incredible. They 
speak of men eating a hundred pounds of meat in a day ; and a Russian 
admiral, Saritcheff, mentions an instance of a man who, in his presence, 
ate at a single meal a mess of boiled rice and butter weighing twenty- 
eight pounds. Although it is difficult to regard these statements with 
entire confidence, the general opinion is undoubtedly well founded that 
the appetite is greater in cold than in warm climates. Dr. Hayes, the 
Arctic explorer, states, from his own observation, that the daily ration of 
the Esquimaux is from twelve to fifteen pounds of meat, about one-third 
of which is fat. He once saw an Esquimau consume ten pounds of walrus 
flesh and blubber at a single meal, which however lasted several hours. 
with the thermometer GO or 70° below zero. Some members of his own 
party manifested a constant craving for fatty substances, and were in the 
habit of drinking the contents of the oil-kettle with evident relish." — 
Flint's Physiology. 

28. Which arc the third of the organic groups? What do they embrace? Points of 
resemblance ? 

24. Origin of the sugars ? Ordinary sugar ? licet -root ? Maple sugar? Crape-sugar t 
Cane-sugar ? 



86 



THE CHEMISTRY OF FOOD 



of sugar are, its power to crystallize when evaporated from 
watery solutions, such as the juices of many plants; a ten- 
dency to ferment, by which process alcohol is produced ; and a 
ready solubility in water. This latter quality renders it very 
easy of digestion, and more so than any other of the saccharine 
group. It is computed that the annual production of sugar, in 
all parts of the world, is more than one million of tons. The 
kind of sugar that is in ordinary use, in this country, is pre- 
pared from the juice of the sugar-cane, which contains eighteen 
per cent, of sugar. In France it is manufactured from the 
beet-root, which holds about nine per cent. ; the maple-tree of 
our climate yields a similar sugar. The sweet taste of fruits 
is due to the presence of grape-sugar: the white grains seen on 
raisins belong to this variety. Cane-sugar is more soluble than 
the latter, and has twice the sweetening power. {Bead Note 10.) 
25. Starch. — This is the most widely distributed of the 
vegetable principles. It is tasteless, inodorous, and does not 

crystallize. It consists of mi- 
nute rounded granules, which, 
under the microscope, reveal 
a somewhat uniform structure 
(Fig. 21). Starch will not 
dissolve in cold water, but in 
boiling water the small grains 
burst open, and may then be 
dissolved and digested. 

26. The bread-stuffs- 
wheat, corn, and rye flours — 
are more than one-half starch. 

Granules of Potato Starch Eice, which is the " staff of 

MAGNIF1ED life" to one-third of the 

human family, contains eighty per cent. Unripe fruits have 
much starch in them, which renders them indigestible when 




Fig. 21. 



10. Why too much Sugar is Injurious. — " Sugar is very wholesome, 
and, as I told you, we want some in our diet. But children will often eat 



25. Starch, how widely distributed ? Its qualities ? Its constituents ? Its solubility ? 

26. How much starch iu bread-stuffs ? Iu rice ? Unripe fruits ? Eipe fruits ? 



THE CHEMISTRY OF FOOD 87 

eaten uncooked, for the grains of raw starch are but slightly- 
acted upon within the body. But, under the potent chemistry 
of the sun's ray, this crude material is converted into sugar. 
Thus are the fruits prepared by the careful hand of Nature, so 
so that when ripe they may be freely used without further 
preparation. 

27. Gum is commonly found in those articles which also con- 
tain starch, and has the same chemical composition as the 
latter, but is much less nutritious. In the East, gum-arabic 
and similar substances are largely employed as food. Persons 
who travel by caravan across vast, sandy deserts, find such 
substances well adapted to their wants, since they are not 
perishable, and are easily packed and carried. 

28. Stimulating Substances. — The three classes of food-prin- 
ciples already considered — the Albuminoids, the Fats, and the 
Sugars — comprise all the more important organic ingredients 
of our food. There are, besides, a great variety of coloring 
and flavoring matters, that stimulate or increase the appetite 
for food by appealing to the eye and taste; but they are not 
nutritious, and are quickly separated from the truly useful 
substances, and do not long remain in the body. Among these 
may be classed spices, flavors of fruits, tea, coffee, and vege- 
table acids. 



too much sugar, just as they will eat too little fat. The harm it. does them 
is — first, it is very apt to spoil the teeth ; second, it takes away the ap- 
petite for other food. If you are always eating sweet cakes and sugar- 
plums, you will not care for plain, nourishing diet. Now, what is best for 
us all is, to have good appetites for wholesome food ; it will do more to 
keep us in health all our lives than anything else ; and there is a great 
deal in getting the right habit." Candies are frequently adulterated with 
plaster- of-paris, chalk, and certain forms of earth, that are indigestible ; 
but worse than that, the coloring matters and flavoring extracts that are 
used in the bright-tinted and fruity-flavored confectionery are absolute 
poisons in many instances, such as arsenic, copper, zinc, Lead, prussic and 
sulphuric acid." — Bei*ner>s Lessons on Health (in part). 



27. Gum, where found ? Its composition ? Gum-Arabic? 

28. The three olasses of food-prindples ? What besides ? What is said of them? Nam< 

the articles not nutritious. 



88 THE CHEMISTRY OF FOOD 

29. Necessity of a Regulated Diet. — A great variety of ex- 
periments have been tried, in order to test the relative value 
of the different nutritive principles. They have been practised 
to some extent upon man, but chiefly upon those inferior 
animals which require a similar diet to man. 

30. By this means it has been demonstrated that — first, 
when any one of these substances is eaten exclusively, the 
body is imperfectly nourished, and life is shortened. Dogs fed 
exclusively upon albumen, fat, or sugar, soon die of star- 
vation. Second, a diet long deprived of any one of these 
principles is a fertile cause of disease ; for example, on ship- 
board, where fresh vegetables are not dealt out for a long 
period, scurvy becomes prevalent among the sailors. They are, 
however, to a certain extent mutually convertible, and thus 
the missing article is indirectly supplied. For instance, sugar 
changes to fat in the body ; and hence, as is well known, the 
" hands " on a sugar plantation grow fat during the sugar season 
by partaking freely of the ripened juices of the cane. (Bead 
Note 11.) 

31. That is the best diet, therefore, which contains some of 
each of these principles, in due proportion; and that is the 
worst which excludes the most of them. The cravings and 
experience of man had unerringly guided him to a correct 
regulation of his diet, long before the chemistry of food was 
understood; so that his ordinary meals long ago combined 

11. The Effects of a Poor Diet. — "The food of the poor in olden 
times was poor and scanty ; so much so, in fact, that their powers of life 
were depressed ; and we believe this fact had much to do with the fearful 
mortality of the plague throughout Europe during the middle ages. The 
lower classes, especially those living in crowded cities, and subsisting on 
the scanty and monotonous diet that the historians of the period describe, 
were the principal sufferers. Erom 1296 to 1666, hundreds of thousands 
were carried off by the most fearful pestilences the earth has ever known. 
Rye in France and oats in England were for generations the almost exclu- 
sive diet ; wheat was a luxury, which even the rich might only indulge in 
at Christmas. Oats were known in Germany 2,000 years ago, and were 
probably the original bread-grain for all Europe." — Dr. J. Knight. 



29. What is said of experiments that have been tried ? 

30. What has been demonstrated in the first place ? Example ? Second demonstra- 
n ? Example ? Give the illustration in relation to convertibility. 



THE CHEMISTRY OF FOOD 



89 



these various principles, the necessity and value of which are 
now explained. {Bead Notes 12 and 13.) 

12. Variety in Diet and in its Preparation Beneficial. — "Every 
dietary should contain fresh vegetables. It is further necessary that cer- 
tain articles belonging to the same class be varied from day to day, other- 
wise the appetite cloys. Beef should alternate with mutton, for example ; 
or variety should be secured by different modes of cooking the same 
article. Indeed, it is not too much to say that the art of cookery is a 
matter of national importance, not only because it renders food palatable, 
but because the more it is studied and practised the greater is the 
economy which may be effected. It is chiefly in this relation, that bever- 
ages, condiments, etc., become such valuable dietetic adjuncts." — Wil- 
son's Hand-book of Hygiene. 

13. Some Experiments as to Food. — "Magendie made numerous 
experiments on the inferior animals to test the value of different forms of 
nutriment. He showed that a diet exclusively composed of starch and 
sugar would not support life. So, too, dogs confined to white bread and 
water died with all the symptoms of starvation ; but on the military 
brown-bread animals lived pretty well, as this article contains a greater 
variety of the alimentary principles. Other experiments have given an 
account of geese limited to some one substance. All of them died — the 
animal fed upon gum, on the sixteenth day ; that fed with sugar, on the 
twenty-first day ; one fed with starch, on the twenty-fourth day ; and one 
fed with white of egg, on the twenty-sixth day. In 1769, before these 
experiments were performed, Dr. Stark, a young English physiologist, 
fell a victim at an early age to ill-judged experiments on himself as to the 
effects of different foods. He lived for forty-four days on bread and 
water, for twenty-nine days on bread, sugar, and water, and for twenty- 
four days on bread, water, and olive oil ; until finally, his constitution 
became broken, and he died from the effects of his experiments." — 
Flint's Physiology. 

TOPICAL OUTLINE 



FOODS 



f ANIMAL 



VEGETABLE 



I MINERAL 



f Nitrogenous . . 

I Non-nitrogenous 
f Nitrogenous . . 

Non-nitrogenous 



f Albumen — ivhite of egg. 
i Caseine — milk and cheese. 
\ Fibrin — blood. 
| Myosin — muscle. 
I Gelatin — bone. 

Fats and sugar. 
f Gluten — cereal (/rains. 
\ Legumen — beans, etc. 
I Starch — all parts of plant? 



Sugars — all parts of plants. 

Gums — all parts of plants. 
I Oils— fruits. 
\ Water, common salt, calcium carbonate, calcium 
\ phosphate, etc. 



90 THE CHEMISTRY OF FOOD 



QUESTIONS FOR TOPICAL REVIEW 

PAGE 

1. What is understood by the term food ? 75 

2. What can you state in relation to the source of food ? 75 

3. What discriminations and selections are necessary ? 75 

4. How can you tell the organic from the inorganic substances? 77 

5. What relative position does water hold as an article of food 77 

6. In what parts of the body is' water found ? 77 

7. In what articles that we eat is it found ? 78 

8. If you were required to go without water or solid food for a number 

of days, which would you pref er to have, and why ? 78 

9. What can you state of the importance of salt as an article of food ?. 78, 79 

10. How abundant is salt, and how does it find its way into the human 

system ? 78, 79, 80 

11. What can you state of the importance of lime in the body? In 

what does it occur ? 80, 81 

12. What, of the importance of iron ? 81 

13. What further is stated of other inorganic substances ? 81 

14. What in relation to organic substances ? 81, 82 

15. What can you state in relation to the albuminoids ? 82 

10. AVhat, in relation to albumen ? 82 

17. AVhat, in relation to caseine ? 83 

18. In relation to the fats or oils, and how generally consumed ? 83, 84 

19. What do we understand by the sugars or saccharine substances ?. . . 85 

20. State what you can of sugar — its origin and various qualities 85, 86 

21. Of starch — its varieties and qualities 86 

22. Of the abundance of starch, and its importance as a food-principle. 86, 87 

23. What is stated in relation to stimulating substances ? 87 

24. Of the necessity for regulation in diet ? 88 

25. What is considered the mosi; healthful diet ? 88, 89 



CHAPTER V 

FOOD AND DRINK 

Necessity for Food — Waste and Bepair — Hunger and Thirst — Amount 
of Food — Renovation of the Body — Mixed Diet — Milk — Eggs — 
Meat — Cooking — Vegetable Food — Bread — The Fotato — Fruits — 
Purity of Water — Action of Water upon Lead — Coffee, Tea, and 
Chocolate — Effects of Alcohol 

1. Necessity for Food. — Activity is everywhere followed by 
waste. The engine uses up coal and water to produce motion, 
the stream wears away its bank, the growing corn-blade draws 
tribute from the soil. When the human body acts, and it is 
always in action during life, some of its particles are worn out 
and thrown off. This waste must constantly be repaired, or 
the body suffers. In this fact is seen the necessity for food. 
The particles, thus worn out, being henceforth useless 4 , are 
removed from the body. Our food and drink are rapidly 
transformed into a new supply of living, useful material, to 
be in turn used up and replaced by a fresher supply. 

2. Waste and Repair. — In this way the healthful body, 
though always wasting, is always building up, and does not 
greatly change in size, form, or weight. At two periods of 
life the processes of waste and repair are not exactly balanced. 
In early life the process of building up is more active, and in 
consequence the form is plump and the stature increases. 
Repair now exceeds waste. On the other hand, when old 
age comes on, the wasting process is more active, the flesh 
and weight diminish, the skin falls in wrinkles, and the senses 
become dull. Only during the prime of life — from about 

1. What follows activity ? Examples ? Necessity for food? 

2. Uivo the theory in relation to waste ami repair. 

01 



92 FOOD AND DRINK 

twenty to sixty years of age — is the balance exact between 
loss and gain. {Bead Note 1.) 

3. Hunger and Thirst. — When the system is deprived of its 
supply of solid food during a longer time than usual, nature 
gives warning by the sensation of hunger, to repair the losses 
that have taken place. This sensation or pain appears to be 
located in the stomach, but it is really a distress of the system 
at large. Let a sufficient quantity of nourishment be intro- 
duced into the system in any other way than by the mouth, 
and it will appease hunger just as certainly as when taken in 
the usual manner. 

4. The feeling of thirst, in like manner, is evidence that 
the system is suffering from the want of water. The apparent 
seat of the distress of thirst is in the throat; but the injection 
of water into the blood-vessels is found to quench thirst, and 
by the immersion of the body in water, the skin will absorb 
sufficient to satisfy the demands of the system. The length 
of time that man can exist without food or drink is estimated 
to be about seven days. If water alone be supplied, life will 

1. The Waste of the Body. — "In the physical life of man there" is 
scarcely such a thing as rest — the numberless organs and tissues which 
compose his frame are undergoing perpetual change, and in the exercise 
of the function of each some part of it is destroyed. Thus, we cannot 
think, feel or move without wasting some proportion, great or small, 
according to the energy of the act, of the apparatuses concerned — such 
as brain, nerve or muscles. Now this waste-product cannot remain in 
its original situation, where it would not only be useless dross, but also 
obstructive and injurious. Such old material is being daily removed 
from our bodies to the average amount of three or more pounds ; and 
that an equal quantity of new shall take its place is the first principle of 
alimentation. To express it in commercial language, the income must be 
equal to the expenditure ; and in each of us the amount of this exchange 
must in a lifetime reach many tons. This tissue- change is so complete, 
that not a particle of our present body will be ours a short time hence ; 
and we will be, as I have lately seen it phrased, like the knife which, 
after having had several new blades, and at least one new handle, was 
still the same old knife to its owner. We are, in fact, constantly ' moult- 
ing.' " — Mapother's Lectures on Public Health. 



3. System deprived of food ? Warning ? What is the pain ? How proved ? 

4. Feeling of thirst ? Seat of the pain ? How proved ? Time a person can exist with- 
out food '? 



FOOD AND DRINK 93 

last much longer — there being cases recorded where men have 
lived twenty days and over without taking any solid food. 
{Bead Note 2.) 

5. Quantity of Food. — The quantity of food required varies 
greatly, according to the individual and his mode of life. The 
young, and others who lead active lives, or who live in the open 
air, require more food than the old, the inactive, or the sed- 
entary. Those who live in cold regions require more than 
the inhabitants of hot climates. Habit, also, has much to do 
with the quantity of food required. Some habitually eat and 
drink more than they actually need, while a few eat less than 
they should. 

6. The average daily quantity of food and drink for a 
healthy man of active habits is estimated at six pounds. This 
amount may be divided in about the following proportions : 
the mineral kingdom furnishes three and one-half pounds, in- 
cluding water and salt ; the vegetable kingdom, one and one- 
half pounds, including bread, vegetables, and fruits; the 
animal kingdom, one pound, comprising meat, eggs, butter, and 
the like. This quantity is about one twenty -fourth the weight 

2. Hunger and Thirst. — " We none of us object to a sharp-set appe- 
tite ; that is by no means unpleasant, especially when there is food at 
hand ; but if this is not the case, it soon becomes a craving passion — a 
strong impelling power. The cravings of hunger have done much for this 
world ; ' look where we may, we see it as the motive power which sets 
the vast array of human machinery in action. ' Hunger is also the incen- 
tive which directs our attention to the system's need for food, and if it 
be sharp enough the most loathsome substances are greedily devoured. 
By it has man, and civilized man, too, been driven to feed upon the 
putrid corpse of his comrade. Plunger is one of the great forces in action 
in the preservation of the life of the individual ; and the fear of it is one 
of the strongest incentives to action. But the pangs of hunger are toler- 
able in comparison with the tortures of raging thirst. In fact, so terrible 
are the latter that they form one of the crudest tortures which man can 
inflict on man ; so cruel a torture, indeed, that it has rarely been used, 
except in cases of bitter personal animosity, by others than brutal Eastern 
tyrants, or bigots under the influence of religious fanaticism." — Fother- 
gill on the Maintenance of Health. 



5. Amount of food required? The young and others? Those living in hot and cold 
climatos ? Habits ? 

fl. Quantity of food daily ? How divided ? Compare with the weight of the body, 



94 



FOOD AND DRINK 



of the body, as it is generally computed ; the average weight 
of an adult man being placed at 140 pounds. A man, there- 
fore, consumes an amount of solid and liquid nutriment every 
twenty -four days equal in weight to that of his body, a corre- 
sponding amount being excreted, or removed from the system in 
the same time. {Bead Notes 3 and 4). , 

3. A Lifetime Allowance of Food. — "M. Soyer, in his 'Modern 
Housewife,' makes a calculation as to how much food an epicure of 70 
years of age has consumed. This imaginary epicure, who is supposed to 
be a wealthy personage, is placed by him on Primrose Hill at ten years 
old and told to look around him at the vast assemblage of animals and 
other objects he will in the course of a lifetime send down his throat — 
the sight of which is, of course, described as appalling. Among the other 
things, he is to devour 30 oxen, 200 sheep, 100 calves, 200 lambs, 50 pigs, 
1,200 fowls, 300 turkeys, 263 pigeons, 120 turbot, 110 salmon, 30,000 
oysters, 5,745 lbs. of vegetables, 243 f lbs. of butter, 24,000 eggs, and 4^ 
tons of bread, besides fruits, sweetmeats, etc., and 49 hogsheads of wine, 
548 gals, of spirits, and about 3,000 gals, of tea and coffee. This is a 
mere outline of what we are told is destined to be consumed. To show 
there is no exaggeration, Soyer assures us that he has from experience 
made up a scale of food for the day for a period of 60 years, and it 
amounts to 33| tons of meat, farinaceous food, and vegetables, etc." — 
Journal of Chemistry. 

4. A Daily Ration for an Adult Man. — " We may arrive at something 
like an average daily diet by taking the case of the man in good health, 
weighing 154 lbs., and measuring 5 feet 8 inches in height. Simply to 
maintain his body, without loss or gain in weight, his ration of food 
should not contain less, during 24 hours, than the following proportions 
and quantities of the main ingredients : 



THE AVERAGE DAILY DIET FOR AN ADULT 



FOOD SUBSTANCES. 


PER CEXTUM. 


T.'EIGHT. 


Water . .- 


SI. 5 
3.9 

10.0 
3.0 

.3 


lbs. oz. grs. 

5 8 320 

4 110 

11 178 

3 33T 

325 

1T0 


Albuminoids or flesh formers 


Fat 


Common salt 

Phosphates, potash, salts, etc 




100. 6 13 123 



" Water, it will be remembered, enters into the composition of every 
article of food as well as in the liquids we drink, In reality, the weight 



FOOD AND DRINK 95 

7. Renovation of the Body. — By this process, so far as 
weight is concerned, the body might be- renewed every twenty- 
four days ; but these pounds of food are not all real nutriment. 
A considerable portion of that which we eat is innutritious, 
and though useful in various ways, is not destined to repair 
the losses of the system. An opinion has prevailed that the 
body is renewed throughout once in seven years ; how correct 
this may be, it is not easy to decide, but probably the reno- 
vation of the body takes place in a much shorter period. 
Some parts are very frequently renewed, the nutritive fluids 
changing more or less completely several times during the day. 
The muscles, and other parts in frequent exercise, change 
often during a year; the bones not so often, and the enamel 
of the teeth probably never changes after being once fully 
formed. {Bead Note 5.) 

8. Mixed Diet. — The habits of different nations in respect 
to diet exhibit the widest and strangest diversity. The civil- 
ized cook their food, while savages often eat it in a raw state. 
Some prefer it when fresh ; others allow it to remain until it 
has become tainted with decay. Those dwelling in the far 

of the dry food we take will exceed that given above ; chiefly for the 
reason that they do not come to us pure and unmixed with fibrous 
material and gelatine, whose use in nourishing the body is limited and 
uncertain." — Kensington Museum Hand-Book on Food. 

5. The Renewal of the Body. — "To meet these constant chemical 
changes, material is taken in, in the form of food and drink, which is 
being constantly assimilated, and so nutrition and repair are conducted. 
The rapidity with which these changes are carried on is much greater 
than is usually supposed. Paley, in his ' Natural Theology,' states that 
seven years are requisite for the perfect renewal of the body ; and this 
statement, owing partly to the mysticism associated with the number 7, 
is generally accepted and believed. The time really is rather months 
than years ; but it is absurd to fix a time which must necessarily vary in 
different individuals, being much less in the infant than in the aged, in 
the active than the indolent; widely different, too, in various tissues, 
from the epithelium lining of the glands of the stomach, renewed several 
times in each act of digestion, to the enamel of the tooth, which is proba- 
bly never renewed during a lifetime." 



T. How often, then, might the body be renewed? Why is it not? Opinion? How 
correct ? What further is stated ? 

S. Habits of nations ? Give the different 0OS6S. 



96 FOOD AND DRINK 

north, subsist almost wholly on animal food, while those living 
in hot climates have bountiful supplies of delicious fruits with 
which to satisfy all their bodily wants. One race subsists 
upon the banana, another upon the blubber of seals. In 
temperate climates, a diet composed partly of vegetable and 
partly of animal food. is preferred. {Bead Note 6.) 

9. The important point to consider is, however, not one of 
origin, but whether the chemical principles (mentioned in the 
last chapter) enter into the composition of the diet. A purely 
vegetable diet may be selected which would contain all the 
principles necessary to sustain life. It is recorded of Louis 
Cornaro, a Venetian noble, that he supported himself comfort- 
ably for fifty-eight years on a daily allowance of twelve ounces 
of vegetable food, and about a pint of light wine. On the 
other hand, the food of John the Baptist, consisting of 
"locusts and wild honey," is an example of the sustaining 
power of a diet chiefly animal in its origin. 

10. In our climate, those- who lead active lives crave an 
allowance of animal food ; and it has been found by experience 
that with it they can accomplish more work and are less sub- 
ject to fatigue, than without it. Among nations where an 
exclusively vegetable diet is employed, indigestion is a dis- 
order especially prevalent. {Read Note 7.) 

6. Different Effects of Animal and Vegetable Food. — "Raw meat 
gives fierceness to animals, and would do the same to man. This is so 
true that the English, who eat their meat underdone, seem to partake of 
this fierceness more or less, as shown in pride, hatred, and contempt of 
other nations." — Be La Mettrie. 

"The carnivora are, in general, stronger, bolder, and more pugnacious 
than the herbivora on which they prey ; in like manner, those nations 
who live on vegetable food differ in disposition from such as live on 
flesh." — Liebig. 

7. A Mixed Diet affords the Best Results. — "The mixed diet to 
which the inclination of man in temperate climates seems usually to lead 
him, when circumstances allow that inclination to develop itself freely, 
appears to be fully conformable to the construction of his dental and 
digestive apparatus, as well as to his instinctive cravings. And whilst 



9. The point to consider ? Vegetable diet ? Louis Cornaro ? John the Baptist? 
10. What has been found in our climate ? Exclusive vegetable diet ? 



FOOD AND DRINK 97 

11. The necessity for occasionally changing or varying the 
diet, is seen in the fact that no single article comprises all the 
necessary principles of food, and that the continuous use of 
any one diet, whether salt or fresh, is followed by defective 
nutrition and disease. There is one exception to this rule : in 
infancy, milk alone is best calculated to support life ; for then 
the digestive powers are incompletely developed, and the food 
must be presented in the simplest form possible. It should 
also be remembered that too rich diet is injurious, just as truly 
as one that is inadequate. When the food of horses is too 
nutritious, instinct leads them to gnaw the wood-work of their 
mangers. 

12. Different Articles of Diet — Milk. — Milk is the earliest 
nutriment of the human race, and in the selection and arrange- 
ment of its constituents, may be regarded as a model food, no 
other single article being capable of sustaining life so long. 
Cow's milk holds caseine, one of the albuminoids, about five 
parts in one hundred ; a fatty principle, when separated, known 
as butter, about four parts ; sugar of milk four parts ; water 
and salts eighty-seven parts. The caseine and fatty substance 
are far more digestible in milk than after they have been sepa- 
rated from it in the form of cheese and butter. 

13. Since milk, in itself, is so rich an article of food, the 
use of it as a beverage is unwise, unless the quantity of the 

on the one hand it may be freely conceded to the advocates of ' vegeta- 
rianism,' that a well-selected vegetable diet is capable of producing, in 
the greatest number of individuals, the highest physical development of 
which they are capable, it may, on the other hand, be affirmed with 
equal certainty, that the substitution of a moderate proportion of animal 
flesh is in no way injurious ; but, so far as our evidence at present 
extends, this seems rather to favor the highest mental development. 
And we can scarcely avoid the conclusion that the Creator, by conferring 
on a man a remarkable range of choice, intended to qualify him for sub- 
sisting on those articles of diet, whether animal or vegetable, which he 
finds most suitable to his tastes and wants." — IT. />. Carpenter on the 
Principles of Physiology. 



11. Necessity for change in diet ? Continuous use of the same diet '.' Exception 
Too rich diet? Horses? 

12. Milk us a model food '? Cow's milk ? The constituents when separated ? 

13. Milk as a beverage ? Milk sold in cities ? How to detect the cheat ? 



98 FOOD AXD BRINK 

other articles consumed be reduced at the same time. The 
milk sold in cities is apt to be diluted with water. The way 
to detect the cheat is by testing the specific gravity of the 
article. Good milk is about 1030 ; skimmed milk, 1035 ; but 
milk diluted one-fifth is 1024. An instrument called the 
lactometer is also used, by which the amount of cream present 
is ascertained. 

14. Eggs. — The egg is about two-thirds water, the rest is 
pure albumen and fat in nearly equal portions. The fat is in 
the yolk, and gives it its yellow color. Eggs contain none of 
the sugar principles, and should be eaten with bread or vege- 
tables that contain them. Soft-boiled eggs are more wholesome 
than those which are hard-boiled or fried, as the latter require 
longer time to digest. 

15. Meats. — The meats, so called, are derived from the 
muscular parts of various animals. They are most important 
articles of food for adults, inasmuch as they are richly stored 
with albuminoid substances and contain more or less fat. Such 
food is very nourishing, and easily digested if eaten when 
fresh, — veal and pork being exceptions. The flesh of young 
animals is more tender and, in general, more digestible than 
that of older ones. All lueat is more tough immediately after 
the killing of the animal, but improves by being kept a certain 
length of time. 

16. Some persons prefer flesh that has begun to show signs 
of decomposition, or is unmistakably putrid. By some, venison 
is not considered to have its proper flavor until it is tainted. 
In England, people prefer mutton that is in a* similar condition, 
just as on the continent of Europe many delight in cheese that 
is in a state of decomposition. In certain less civilized coun- 
tries, flesh is not only eaten uncooked, but in a mouldy, rotten 
condition. The use of such food is not always immediately 
injurious, but it predisposes to certain diseases, as indigestion 
and fevers. (Bead Xote 8.) 



14. Composition of eggs ? Yolk ? How should eggs be eaten ? Why ? How boiled ? 
Why '? 

15. Meats, whence derived ? Why important ? Flesh of young animals ? 

16. Preference of oersons ? Venison? Mutton? Cheese? Uncooked flesh ? 



FOOD AND DRINK 99 

17. Cold is one means of preserving meat from decay. In 
the markets of northern Russia, the frozen carcasses of animals 
stand exposed for sale in the winter air for a considerable time, 
and are sawed in pieces, like sticks of wood, as the purchases 
are made — such meat, when thawed, being entirely lit for 
food. Beef and pork are preserved by salting down in brine, 
and in this condition may be carried on long voyages, or kept 
for future use. Salted meat is not as nutritious as fresh, since 
the brine absorbs its rich juices and hardens its fibres. Long- 
continued use of salt meats, without fresh vegetables, gives 
rise to the disease called scurvy, formerly very prevalent on 
ship-board and in prisons, but now scarcely known. 

18. Cooking. — The preparation of food by the agency of fire 
is of almost universal practice, even among the rudest nations. 
The object of cooking is to render food more easy of digestion 
by softening it, to develop its flavor, and to raise its tempera- 
ture more nearly to that of the body. A few articles of flesh- 
food are eaten uncooked in civilized lands, the oyster being 
an instance. Raw meat is occasionally eaten by invalids 
with weak digestive powers, and by men training for athletic 
contests. 

19. The cooking may be so conducted as to rob the meat of 
its tenderness, and of its flavor. The proper method, in order 

8. A Summary Concerning Diet. — " The food on which the man who 
would be healthy should live, should be selected so as to insure a variety 
without excess. Animal food should not be taken oftener than twice 
daily. The amount of animal and vegetable food combined should not 
exceed 30 ounces in the 24 hours ; and for the majority of persons an 
average of 24 ounces of mixed solid food, a third only of which should be 
animal, is sufficient. All animal foods should be eaten while they are 
fresh, and after they been have well cooked. The habit of eating under- 
done flesh is an almost certain cause of parasitic disease. The amount of 
fluid taken, in any form, should not exceed the average of 2 4 ounces 
daily. Water is the only natural beverage." —Dr. B. W. Jiichanhon, 
The Diseases of Modem Life. 



17. Cold as a preserver? Meat in Russia? Beef ami pork, how preserved? Sailed 
meat as food ? Scurvy ? 

18. The antiquity of the custom of cooking food? Object of cooking? The oyster? 
Raw meat as an occasional food ? 

10. Effect of boiling meat? How may the cooking be done? The proper mcUhod ? 
Effect? Making of soup? 

L.ofC. 



100 FOOD AND DRINK 

to preserve or promote these qualities, is to place the meat in 
boiling water, which, after a few minutes, should be reduced 
in temperature. In this way the intense heat, at first, coagu- 
lates the exterior layers of albumen, and imprisons the delicate 
juices; after that, moderate heat best softens it throughout. 
When soup is to be made an opposite course should be pursued ; 
for then the object is to extract the juices and reject the fibre. 
Meat, for such purpose, should be cut in small pieces and put 
into cold water, which should then be gradually raised to boil- 
ing heat. {Read Note 9.) 

20. Boasting is probably the best method of cooking meat, 
especially "joints" or large pieces, as by this process the meat 
is cooked in its own juices. Roasting should begin with intense 
heat, and be continued' at a moderate temperature, in order 
to prevent the drying out of the nutritious juices, as by this 
process an outer coating or crust of coagulated albumen is 
formed. During this process the meat loses one-fourth of its 

9. Cooking Paves the Way for Easy Digestion. — The objects to be 
obtained by cooking meat are : 1. To coagulate the albumen and blood 
of the tissues, so as to render the meat agreeable to the sight. 2. To 
develop flavors, and to make the tissue crisp, as well as tender, and there- 
fore more easy of mastication and digestion. 3. To secure a certain 
temperature, and thus to be a means of conveying warmth to the system. 
4. To kill parasites in the tissues of the meat. 

The action of heat should not be continued after these objects are 
accomplished, as the meat will thereby be rendered indigestible. If a 
piece of meat be placed in water which is briskly boiling, a crust, so to 
speak, is formed by the rapid coagulation of the albumen upon and near 
the surface; so that the juice of the meat cannot escape, nor the water 
penetrate its interior. If, on the other hand, the meat be put in cold 
water, and slowly heated, the meat is left poor and tasteless. Even in 
roasting meat the heat must be strongest at first, and it may then be 
much reduced. The juice which, as in boiling, flows out, evaporates, in 
careful roasting, from the surface of the meat, and gives to it the dark 
brown color, the lustre, and the strong aromatic taste of roast meat. ' All 
baked and roasted fatty foods are apt to disagree with delicate stomachs : 
and it is often remarked that, although bread and butter, boiled puddings, 
boiled fish, or boiled poultry can be eaten freely without discomfort, yet 
toast and butter, or meat pies and pastry, or fried fish, or roasted fowl 
will disagree with the stomach. — Letheby on Food. 



20. Roasting ? How should it be done ? Give the philosophy of the process. Frying ? 



FOOD AND DRINK 101 

weight, but the loss is almost wholly water, evaporated by the 
heat. - Too intense or prolonged heat will dry the meat, or 
burn it. Frying is the worst possible method, as the heated 
fat, by penetrating the meat, or other article placed in it, dries 
and hardens it, and thus renders it indigestible. 

21. Trichina. — It should be remembered that ham, sausages, 
and other forms of pork should never be eaten in a raw or 
imperfectly cooked condition. The muscle of the pig is often 
infested by a minute animal parasite, or worm, called trichina 
spiralis. This worm may be introduced alive, in pork food, 
into the human body, where it multiplies with great rapidity, 
and gives rise to a painful and serious disease. This disease 
has been prevalent in Germany, and cases of it occur from 
time to time in this country. 

22. Fish. — The part of fish that is eaten is the muscle, just 
as in the case of the meats and poultry. It closely resembles 
flesh in its composition, but is more watery. Some varieties are 
very easy of digestion, such as salmon, trout, and cod ; others 
are quite indigestible, especially lobsters, clams, and shell-fish 
generally. A diet in which fish enters as the chief article, is 
ill adapted to strengthen mind or body, while its continued 
use is said to be the fertile source of nearly every form of 
disease of the skin. Some persons are so constituted that they 
can eat no kind of fish without experiencing unpleasant results. 

23. Vegetable Food. — The list of vegetable articles of diet 
is a very long one, including the grains from which our bread- 
stuffs are made, the vegetables from the garden, and the fruits. 
All the products of the vegetable kingdom are not alike useful. 
Some are positively hurtful ; indeed the most virulent poisons, 
as strychnia and prussic acid, are obtained from certain vege- 
tables. Again, of such articles as have been found good for 
food, some are more nourishing than others ; seme require very 
little preparation for use, while others are hard and indigest- 



21. What, is " Trichina? " llow guarded against ? 

22. What part of tish is eaten? What does it resemble? Fish as food for digestion; 
Fish as a diet ? 

28. List of vegetable articles? Usefulness of the different vegetables? Strychnia? 
What further is said in relation to the nourishing and other qualities of vegetables ? 



102 FOOT) AND DRINK 

ible, and can only be used after undergoing many preparatory 
processes. Great care must therefore be exercised, and many 
experiments made, before we can arrive at a complete knowl- 
edge in reference to these articles of diet. Tea, coffee, and 
other substances from which drinks are made are of vegetable 
origin. 

24. Bread. — Wheat is the principal and most valuable kind 
of grain for the service of man. Bread made from wheat-flour 
has been in use for many hundreds of years, and on this 
account, as well as because of its highly nourishing properties, 
has been aptly called " the staff of life." We never become 
tired of good bread as an article of daily food. The white 
kinds of flour contain more starch and less gluten than the 
darker, and are therefore less nutritious. The hard-grain wheat 
yields the best flour. In grinding wheat, the chaff or bran is 
separated by a process called "bolting." Unbolted flour is 
used for making brown or Graham bread. {Bead Note 10. ) 

25. The form of bread most easily digested is that which 
has been "leavened," or rendered porous by the use of yeast, 
or by some similar method. Unleavened bread requires much 
more mastication. Hot bread is unwholesome, because it is 
not firm enough to be thoroughly masticated, but is converted 
into a pasty, heavy mass, that is not easily digested. 

10. Bread. — "The health and power of a nation, as of an army, 
depend greatly on its food. The quality of bread in any nation, com- 
munity, or family is a pretty good measure of its civilization. No one 
can entirely dispense with it. Good or bad, in some form it must be had. 
So it is, and has been from the earliest records of the race, and so it will 
doubtless continue. Leavened or fermented bread is as old as the time 
of Moses, and its value has been fully tested. Whatever be the precise 
action of the leaven, it transforms the grain by partial decomposition of 
its original elements, and leaves as its resultant what all men in all ages 
have approved. Is the art of making good, honest, leavened, Bible bread 
lost in Massachusetts, as some of our friends declare ? Baker's bread is 
almost universally adulterated. Bread hastily made in families is mixed 
in a variety of ways, with a variety of chemicals, and is generally imper- 



24. Wheat? " Staff of life ? " White flour? Hard-grain wheats ? Bolting? Graham 
bread ? 

25. Leavened bread ? Unleavened ? Hot bread ? 



FOOD AND DRINK 103 

26. Wheaten bread contains nearly every principle requisite 
for sustaining life, except fat. This is commonly added in 
other articles of diet, especially in butter, — " bread and butter," 
consequently, forming an almost perfect article of food. The 
following experiment is recorded : " A dog eating ad libitum of 
white bread, made of pure wheat, and, freely supplied with 
water, did not live beyond fifty days. He died at the end of 
that time with all the signs of gradual exhaustion." Death 
took place, not because there was anything hurtful in the 
bread, but because of the absence of one or more of the food 
principles. 

27. The Potato. — The common or Irish potato is the vege- 
table most extensively used in this country and Great Britain. 
Among the poorer classes in Ireland it is the main article of 
food. While it is not so rich in nutritious substances as many 
others, it has some very useful qualities. It keeps well from 
season to season, and men do not weary of its continuous use. 
It is more than two-thirds water, the rest being chiefly starch, 
with a little albumen. 

28. The sweet potato differs from the white or common in 
containing more water and a small proportion of sugar. The 
common potato and the tomato belong to the same botanical 
order as the " nightshades," but do not possess their poisonous 

fectly cooked. Very often the elements of wheat and fat which the body 
demands "(a wise and witty clergyman of the last generation used to say, 
' bread is the staff of life, but bread and butter is a gold-headed cane ') 
are furnished in underdone pastry, made from flour and hog's lard. Any 
family who will take the pains can have good bread. It involves not 
more than ordinary skill and judgment. It is to be found on the con- 
tinent of Europe, on all the great lines of travel, and is as common 
among the people of France and Germany as it is rare with us. The 
materials for an honest, wholesome loaf are simple and not expensive. 
The value of time and labor required for kneading the dough are the 
only difficulties, and these we would not undervalue ; they are in many 
families very serious, and not easily overcome. " — Derby on the Food of 
Massachusetts. 

26. Wheaten bread ? Bread and butter ? Experiment on the dog f 

27. State what is said of the Irish potato. 

28. Sweet potato? Nightshades? Potatoes when germinating} 



104 FOOD AND DRINK 

qualities, unless we except potatoes that are in the process of 
germination or sprouting, when they are found injurious as 
food. 

29. Fruits. — These are produced, in this country, in great 
abundance, and are remarkable alike for their variety and 
delicious flavor; consequently they are consumed in large 
quantities, especially during the warmer months. The moder- 
ate use of ripe fruits, in their season, is beneficial, because 
they offer a pleasant substitute for the more concentrated diet 
that is used in cold weather. The amount of solid nutriment 
they contain is, however, small. The percentage of water in 
cherries is seventy-five, in grapes eighty-one, in apples eighty- 
two. Unripe fruits contain starch, which, during the process 
of ripening, is converted into sugar. Such fruits are indi- 
gestible, and should be avoided; cooking, however, in part 
removes the objection to them. 

30. Pure Water. — It is important that the water we drink 
and use in the preparation of food should be pure. It should 
be clear and colorless, with little or no taste or smell, and free 
from any great amount of foreign ingredients. Chemically 
pure water does not occur in nature; it is obtained only by 
the condensation of steam, carefully conducted, and is not as 
agreeable for drinking purposes as the water furnished by 
springs and streams. Rain-water is the purest occurring in 
nature ; but even this contains certain impurities, especially 
the portion which falls in the early part of a shower ; for in 
its descent from the clouds, the particles floating in the air are 
caught by the falling drops. 

31. Water from springs and wells always contains more or 
less foreign matter of mineral origin. This imparts to the 
drink its pleasant taste — the sparkle, or "life," coming from 
the gases absorbed by the water during its passage under- 

29. Fruits ? Use of ripe fruit ? Nutriment they contain ? Starch in unripe fruits ? 
Cooking of unripe fruits? 

30. How should drinking-water be as regards color and smell ? Chemically pure water ? 
How obtained ? Agreeableness of perfectly pure water ? 

81. Spring and well water ? Whence the sparkle, or life ? The water supply of cities ? 
Croton water ? Ridgewood ? 



FOOD AND DRINK 105 

ground. The ordinary supply of cities is from some pure 
stream or pond, conveyed from a distance through pipes, the 
limpid fluid containing generally only a small amount of im- 
purity. Croton water, the supply of New York City, is very 
pure, and contains only four and a half grains to a gallon ; the 
Bidgewood water, of Brooklyn, holds even less foreign matter. 

32. Drinking-water may contain as large a proportion as 
sixty to seventy grains per gallon of impurity, but a much 
larger quantity renders it unwholesome. The mineral spring 
waters, used popularly as medicines, are highly charged with 
mineral substances. Some of them, such as the waters at 
Saratoga, contain three hundred grains and more to the gallon. 
{Bead Note 11.) 

33. Action of Water upon Lead. — The danger of using water 
that has been in contact with certain metals is well known. 

11. Impure Water Spreads Disease. — "In the year 1867, three 
millions of pilgrims, of whom a handful had come from a cholera dis- 
trict, assembled at Hurdwar, a few miles from the spot where the Ganges 
escapes from the Himalayas. On the 12th of April the three millions 
resolved to bathe and drink. ' The bathing-place of the pilgrims was a 
space 650 feet long by 30 feet wide, shut off from the rest of the Ganges 
by rails. Into this long and narrow inclosure pilgrims from all parts 
of the encampment crowded as closely as possible from early morn to 
sunset ; the water within this space, during the whole time, was thick 
and dirty — partly from the ashes of the dead, brought by surviving 
relatives to be deposited in the water of their river god, and partly from 
the washing of the clothes and bodies of the bathers. Now, pilgrims at 
<the bathing ghaut, after entering the stream, dip themselves under the 
water three times or more, and then drink of the holy water, whilst 
saying their prayer. The drinking of the water is never omitted ; and 
when two or more members of a family bathe together, each from his 
own hand gives to the other water to drink. On the evening of the next 
day, the 13th of April, eight cases of cholera were admitted into one of 
the hospitals at Hurdwar. By the 15th, the whole of this vast concourse 
of pilgrims had dispersed,' carrying the cholera in every direction over 
India; it attacked the British troops along the various routes, it passed 
the northern frontier, got into Persia, and so on into Europe, where it 
will work its wicked will for some time to come. That is a sample of 
the mischief water can do in the way of spreading disease." - London 
Medical Press. 

82, Impurities in drinking-water ? Mineral springs? 
$?. What is stated of the aotlon of water upon load? 



106 FOOD AND DRINK 

Lead is one of the most readily soluble, and probably the most 
poisonous of these substances in common use. When pure 
water and an untarnished surface of lead come in contact, 
the water gradually corrodes the metal, and soon holds an 
appreciable quantity of it in solution. When this takes place 
the water becomes highly injurious ; the purer the water, and 
the more recent the use of the metal, the greater will be the 
danger. {Read Note 12.) 

34. In cities, lead pipes are commonly used to convey water 
through the houses ; lead being also used in the construction of 
roofs, cisterns, and vessels for keeping water and other liquids. 
After articles made of lead have been in use several months, 
the danger of lead-poisoning diminishes. An insoluble coating 
of the sulphate of lead forms upon the exposed surface, thus 
protecting it from further corrosion. It is, however, a wise 
precaution, at all times, to reject the water or other fluid that 
has been in contact with leaden vessels over night, or for a 
number of hours. Allow the water in pipes to run freely 
before using. 

35. Coffee. — This is an important addition to diet, and, if 
moderately used, is beneficial to persons of adult age. As 
commonly employed, it consists of an infusion in boiling water 
of the roasted and ground berry. The water extracts certain 
flavoring and coloring matters, but that which gives it its 
peculiar stimulant qualities is the alkaloid caffeine. With most 
persons its action is that of a gentle stimulant, without any 
injurious reaction. It produces a restful feeling after exhaust- 

12. Lead in Drinking- Water. — " The danger of using lead for pipes 
or cisterns is now well known, the case of the late royal family of France, 
at Claremont, having made the matter notorious. In this case there was 
one-tenth of a grain in the gallon, and one-third of the persons who 
drank the water were affected. But even one one-hundredth of a grain 
per gallon has produced palsy in those who drank this impurity habitually. 
It is remarkable that the Thames water will at one time dissolve lead, 
and not at another." — Mapother's Health Lectures. 



34. Lead in pipes and other things ? Advice ? What takes place after the articles of 
lead have been used much ? What is wise ? 

35. Coffee as an article of diet ? Of what does it consist ? How does the water affect 
the coffee ? The peculiar stimulant ? How does it affect most persons ? 



FOOD AND DRINK 107 

ing efforts of mind or body ; it tranquillizes, but does not dis- 
qualify for labor, and hence it is highly esteemed by persons 
of literary pursuits. 

36. Another property of coffee is, that it diminishes the 
waste of the tissues, and consequently permits the performance 
of excessive labor upon an economical and inadequate diet. 
This has been tested among the miners of Belgium. Their 
allowance of solid food was below that found necessary in 
prisons and elsewhere; but, with the addition of about four 
pints of coffee daily, they were enabled to undergo severe 
labor without reducing their muscular strength. The caravans 
which traverse the deserts are supported by coffee during long 
journeys and lengthened privation of food. Among armies it 
is indispensable in supplementing their imperfect rations, and 
in relieving the sense of fatigue after great exposure and long 
marches. When taken with meals, coffee is also thought to 
promote digestion. 

37. Tea. — The effects of tea-drinking are very similar to 
those of coffee, and are due to a peculiar principle called theine. 
This principle is probably the same as that found in coffee — 
caffeine — since the chemical composition of both is precisely 
alike. Tea, as a beverage, is made from the dried leaves of 
the plant by the addition of hot water ; if the tea be boiled, 
the oil which gives it its agreeable flavor is driven off with the 
steam. There are two kinds of tea — the black and the green ; 
the latter is sometimes injurious, producing wakefulness and 
other nervous symptoms. The excessive use of either coffee 
or tea will cause wakefulness. 

38. During Dr. Kane's expedition in the Arctic regions, the 
effects of these articles were compared. " After repeated trials, 
the men took most kindly to coffee in the morning, and tea in 
the evening. The coffee seemed to continue its influence 
throughout the day, and they seemed to grow hungry less 



3G. Another property of coffee ? Miners of Belgium ? The Caravans * Among armies ? 
Taken with meals ? 

37. Effects of tea-drinking? Peculiar principle ? The tea beverage, how made S Blaok 
and green tea? Excessive use of tea or coffee '■' 

88. Experiments made during lvuuo's expedition ? 



108 FOOD AND DRINK 

f 
rapidly than after drinking tea, while tea soothed them after a 
day's hard labor, and the better enabled them to sleep. They 
both operated upon fatigued men like a charm, and their supe- 
riority over alcoholic stimulants was very decided." 

39. Chocolate is made from the seeds of the cocoa-tree, a 
native of tropical America. Its effects resemble somewhat 
those of tea and coffee, but it is very rich in nutriment. Lin- 
naeus, the botanist, was so fond of this beverage, that he gave 
to the cocoa-tree the name Theobroma — "the Food of the 
Gods." Its active principle is tlieobromin. 

40. Alcohol. — The word alcohol is of doubtful origin. It is 
commonly supposed to be derived from the Arabic language, 
several words in that tongue resembling it in sound, but none 
of them or any other in the language have a meaning corre- 
sponding with that of the English term. 

41 . History. — Alcohol was distilled from rice many centu- 
ries before that seed was known in Europe. We hear of it in 
Bagdad about the year 900. It was known to the Moors of 
Spain, through whom the knowledge of its production spread 
into Western Europe. The first description of alcohol was 
given by a western writer about 1280, who wrote of a " burning 
or ardent water " that resulted from the distillation of wine. 
It may also have been known to the Romans, for Pliny, in 
the first century, wrote of a strong kind of wine that was in- 
flammable — a quality that strongly suggests the knowledge 
of a product of distillation. 

42. The Alcohols. — There are at least twelve members of 
the alcohol family, the oldest of which is common alcohol. 
This last is the only one that need be referred to here. Com- 
mon Alcohol is sometimes known as spirit of wine, also as 
vinic alcohol. It is commonly obtained by the distillation of 
grains or of wine. The ardent spirits of commerce (brandy, 
whiskey, gin, and rum) contain about one half water, the other 

39. State what is said of chocolate. 

40. In what language has the word alcohol its origin ? 

41. Give its history. 

42. How is common alcohol obtained ? 



FOOD AND DRINK 109 

half alcohol. Alcohol is also found in all the wines and malt 
liquors (beer, ale, and porter) in varying proportions. The 
juices of ripe, sweet fruits will, at seventy degrees Fahren- 
heit, begin spontaneously to " work " or ferment ; also wheat 
and other starch-grains, when sprouting, will have their starch 
changed into sugar, and this, in like manner, will undergo 
fermentation — alcohol being one of the results of this action 
in both cases. Thus this fermentation, in changing barley, 
grapes, and apples, into beer, wine, and cider, respectively, 
transforms valuable foods into most seductive poisons. 

43. Properties of Alcohol. — Alcohol is a clear, colorless, 
volatile, and inflammable liquid of penetrating odor and 
burning taste. It is lighter than water. As it cannot be 
frozen, it is used in thermometers for taking low or exceedingly 
cold temperatures. It is also used in spirit levels. It burns 
with a pale, bluish flame, without smoke, and with intense 
heat ; hence its use in the spirit-lamp. 

44. Is Alcohol Food ? — Some authorities class alcohol among 
the food substances. Chemically it is allied to the sugars, but 
the effect of alcohol within the body is very unlike that of the 
sugars. The latter are nourishing, while the former tends to 
impair nutrition. It was on the mistaken theory that alcohol 
had sustaining power, that for two hundred years the armies 
and navies of certain countries were supplied with rations of 
rum or some other alcoholic drink, under the name of '•grog/' 
During recent years, a systematic inquiry has been made to 
discover whether the grog-ration was really serviceable or the 
reverse. Tests have been tried upon considerable bodies of 
men, under military discipline, by withdrawing that ration; 
comparisons have been made at home and abroad, in hot cli- 
mates and in cold, in active service and at rest. The results 
of these observations have, without exception, been favorable to 
the non-use of spirits. The proportion of ill-health, the num- 
ber of sick days, and the incapacity for work have invariably 
been greater among the men to whom the spirit-ration has been 

43. What are the properties of alcohol ? 

44. What can you say of alcohol us a food * 



110 FOOD AND DRINK 

issued, -the quality of food and other circumstances being made 
as nearly equal as possible. Hence the conclusion that not 
only is alcohol not a food, but is injurious in itself, and a 
detriment to the food taken. 

45. Does Alcohol Relieve Thirst? — One of the most striking 
properties of alcohol is its affinity to water. When swallowed, 
therefore, its tendency is to deprive the body of water, and to 
create thirst rather than to relieve it. It may then be stated 
that alcoholic drinks which appear to quench thirst do so by 
means of the water that, in greater or less quantities, dilutes 
the alcohol they contain. Water, the peerless beverage of 
nature, does its work better in proportion as it remains free 
from alcohol. To maintain normal action, the delicate organs 
of the body require a uniform supply of water. When alcohol 
is introduced, it draws the water to itself, and leaves the organs 
without their share of proper moisture ; hence, after death from 
alcoholism, we find them affected in different degrees, being 
drier and harder than is natural. 

46. Does Alcohol Enable its Consumers to Resist Extreme 
Cold? — If this could be proved to be a fact, some of its 
boasted usefulness would receive support. In extreme cold 
climates, the inhabitants are enabled to live comfortably by 
consuming vast quantities of animal food alone, especially if it 
is abundantly oily. Will alcohol act in a similar way or assist 
in maintaining heat ? Experience and observation say no. 

47. Before the thermometer was applied to the testing of 
the body's temperature, it was commonly supposed, by reason 
of the sensations of warmth, that alcohol increased bodily heat. 
When, however, this new test was applied, it became apparent 
that those sensations were deceptive, and that there had been 
an actual fall in temperature as the result of imbibing alcohol. 
The surface of the stomach is irritated by this powerful agent, 
causing the nerves of sensation to convey to the brain the im- 
pression that something has entered the stomach which is pro- 



45. Does alcohol relieve thirst? 

46. Does alcohol enable one to resist cold ? 

47. How is the temperature pf the body affected ? 



FOOD AND DRINK 111 

ducing warmth. This is a delusive impression, as we know, 
by pouring a few drops of alcohol on the skin, that the ten- 
dency of alcohol is to cool the surface whenever evaporation 
can take place. 

48. The sensation of warmth of the face and surface of the 
body is also deceptive. The flushing of the face, common to 
hard drinkers, does not indicate that they have a superabun- 
dance of animal heat, the temperature of their bodies being 
below normal. The true cause of the flush is a paralysis of 
one set of nerves governing the natural action of the hair-like 
vessels that course just below the skin. Nature has provided 
these infinitely fine vessels with minute controlling nerves, 
whose duty it is to regulate the flow of blood in exposed 
positions. Alcohol paralyzes this control ; the blood flows at 
random, and the terminal vessels are overcharged with blood. 
Hence, the high color, which is so remarkable in habitual 
drinkers that it amounts to a disfigurement, is Nature's signal 
of distress, showing that the circulation is deranged, and the 
blood unduly brought into contact with the lower temperature 
of the outer air. Alcohol, therefore, is not a producer of heat, 
but a promoter of cold, and must be dangerous to any persons 
taking it when they are exposed to low temperatures. {Read 
Note 13.) 

49. The testimony of those who ha\^ had experience in 
contact with the realms of snow and ice is unanimous against 
the cold-resisting property of alcohol. It is recorded of the 
men who served in Napoleon's campaign in Russia, under 
great exposure to cold, that death was hastened by the use of 
alcohol. The evidence of the Monks of St. Bernard is similar. 



13.. Dr. Rae's Statement. — "The Arctic explorer, Dr. Rae, states 

that lie found entire avoidance of alcohol necessary in the far North. The 
moment a man had swallowed a drink of spirits, it was certain that his 
day's work was: nearly at an end. l It was absolutely necessary that the 
ride of total abstinence should be rigidly enforced, if we would accomplish 
our day's task. Any use of liquor, as a beverage, when we had work on 
hand, in that terrific cold, was out oi the question.' " 



48. Of what is the flushed Rice of drinkers the index* 
4i». Wlmt. do travelers in uold countries saj of its use ? 



112 FOOD AND DRINK 

Numerous Arctic explorers testify that not only is the tem- 
porary indulgence liable to result in most serious consequences, 
but that strong, able-bodied men in the habit of using alcoholic 
drinks are entirely unfitted to resist the cold to which they 
must be exposed. The natives and travelers alike rely upon 
fresh animal food, especially fatty food, and avoid alcohol as a 
danger to life.* 

50. Alcohol Destructive to Life. — Instead of being a pro- 
moter of life, as the early alchemists who produced it hoped 
it would be, alcohol is hostile to life; it is a poison. Plant 
life is speedily destroyed when brought into close contact with 
it. The lower animals are poisoned by it. When applied 
directly to small insects and reptiles, death commonly occurs 
in a few seconds or minutes. It is hurtful to the larger ani- 
mals, and the more intelligent of them appear to resent its 
use instinctively. This is seen when dogs have been forced to 
take brandy in small doses for some time. Instead of learn- 
ing to like it, they gradually show a greater and greater dis- 
like to it. 

51. The Proper Usa of Alcohol. — Like opium, chloral, 
arsenic, and many other poisons, alcohol may be rightly 
used, and that is as a medicine. For the relief of sickness 
and feebleness of body, or conditions of unusual fatigue, 
alcohol can be benefk^ally used under the advice of a physi- 
cian. Like the other poisons, it should be definitely pre- 
scribed and the size and number of the doses precisely ordered 
by the physician. 

52. Errors in the Use of Alcohol. — If this view of the ques- 
tion is the correct one, how utterly foolish is the practice of 
those who are continually prescribing for themselves doses of 
this poisonous substance for any trifling disturbance of their 

* "Alcohol is not the warming cordial and invigorating stimulant that 
it is reputed to be, but there is a world-full of preconceived opinions in 
its favor that must be met and overcome before the true view can make 
its way. But the truth must prevail at last. Its true place is not along 



50. What is the effect of alcohol upon life ? 

51. What is the proper use of alcohol ? 

52. What three errors mentioned ? 



FOOD AND DRINK 113 

health. And how much worse is the practice of taking the 
various forms of alcohol when the person so taking them is in 
good health and merely indulges in drinking for the purpose 
of bringing about a temporary stimulation. And worse than 
all the others is the practice of those who not only indulge in 
these stimulants themselves, but who ask others to join in 
with them under the name of good-fellowship, when none of 
them are to be benefited by so doing, but rather all of them 
are in danger of being injured by the act. 

53. This practice, last referred to, is often mistakenly 
spoken of as a sign of generosity, and is ordinarily called 
"treating." It is wholly indefensible from a physiological 
point of view, being harmful both to body and mind; and 
from a social point of view is without its equal for the evil 
that it has wrought and is capable of working. The "social 
glass " and the " treat at the bar " count a hundred victims to 
every other single one that can be traced to any other mistaken 
practice of human society. It is in regard to the evils that 
flow from this false show of generosity and geniality that the 
minds of the young should early be instructed. It is a well- 
established fact that, in some people, alcohol has the power to 
create a craving for more. Their nervous systems become so 
easily poisoned by its use that they must have more, and they 
have not the will-power to resist the temptation. This ten- 
dency to be so easily poisoned is also hereditary in some fami- 
lies, producing drunkards for several generations. 

54. Moderation Societies. — " Moderation societies " have been 
organized to check the evils of " treating," but they have not 
met with success, and it is not to be expected that they will, 
for there can be no moderation in the use of this dangerous 
drug except in the way mentioned at the beginning of this sta- 
tion, namely, as a prescribed medicine. As Dr. Alden has 

with the displays of wealth and luxury upon our sideboards, but in \\w 
medicine-chest along with hasheesh, henbane, opium, stramonium, and 
so forth, labeled as a Poison ! " — Dr. A. F. Kinne. 



58. What is .said of treating ? Is alcohol deceptive ? 
54. What is saiu wf moderation societies? 



114 FOOD AND DRINK 

said, " There is no such thing as a temperate use of spirits. 
In any quantity they are an enemy to the human constitution. 
Their influence upon the physical organs is unfavorable to 
health. They produce weakness, not strength; sickness, not 
health; death, not life." 

55. Diminished Use of Alcohol as Medicine. — As a medicine, 
alcohol is far less freely used by physicians now than formerly. 
The dangers from its use are more generally recognized, and 
other remedies have been discovered and brought into use that 
are fully as efficient and active, but have not the tendency to 
habit-forming that is so peculiar to alcohol and other narcotics. 
There are able physicians who refuse to employ any form of 
alcohol as stimulant or medicine, in the belief that it can be 
safely and happily replaced by other remedies. In London 
and some other cities, hospitals have recently been organized 
and are now being operated on the basis of total abstinence 
from alcoholic treatment. In many parts of England the use 
of alcohol has greatly declined in the alms-houses and other 
public institutions, in which formerly the amount of stimu- 
lants annually consumed was very great. 

56. It is well known that alcohol is an ingredient in many 
of the "Bitters" and other so-called patent medicines that 
have come into popular use through advertisement in the 
newspapers. Many persons have been deluded into the use of 
these, to them, doubly bitter substances ; for, not only have 
they not found the curative results falsely proclaimed in the 
papers, but they have been beguiled into habits of drinking 
and into a liking for alcohol that the "Bitters" soon fail to 
satisfy. 

57. Concerning the Purity of Alcoholic Beverages. — It is well 
known that many makers and friends of wines and liquors 
claim that when these articles are pure they are not injurious, 
but that they become hurtful after they leave their place of 
manufacture by reason of the impurities that are added to 
them by unscrupulous dealers. "Pure and good liquor," they 

55. Is alcohol as highly valued in medicine now as formerly ? 

56. The effect of Bitters ? 

57. What do wine-dealers sny ? What is the harmful element ? 



FOOD AND DRINK 115 

say, " does no harm." Is this correct ? It cannot be denied 
that deadly additions have been, and may be, so made that 
these beverages will become more speedily and manifestly 
poisonous than they would otherwise be, but the teaching of 
modern physiology is this : that so long as the main element 
of danger — that same alcohol from which they get their 
stimulating and seductive properties — is present, the ques- 
tion of purity, or age, or smoothness of taste is one of little 
importance. The "unclean thing," as the Bible calls it, is 
present in all intoxicants, whether they be old and costly, or 
cheap and new and fiery to the taste. {Bead Note 14.) 

58. This so-called " purity " is commonly an accompaniment 
of high cost, especially as applied to wines, and represents 
money or capital that has long been lying idle in order that 
the commodities in question may acquire " age " and smooth- 
ness to the palate. "Purity" is therefore largely the cry of 
the .seller, who is anxious to get back his invested capital, with 
interest, or perhaps with usury. It should be clearly under- 
stood that the best of these drinks, even though obtained from 
the vineyards or wine-cellars of princes, are injurious, and that 
the word " purity " is, in the light of science, a misnomer Avhen 
applied to any beverage that contains alcohol. {Bead Note 15.) 

14. Adulteration in Liquors. — " It is not enough that alcoholic drinks 
are dangerous when purely made, but there is an added danger growing 
out of the almost universal practice of the manufacturers of these drinks 
to tamper with them and adulterate them with other harmful materials. 
Not many months ago the city government of Paris caused a testing of 
all the wines that were brought into the market during a month ; there 
were 1,518 samples of French wine examined, and only 65 found abso- 
lutely free from injurious addition — that is, less than 5 per cent, was 
really pure." — N. Y. Scientific Times. 

15. Adulteration of Wine. — The difficulty in the way of getting pure 
wine is nothing new. Pliny, who lived eighteen hundred years ago, wrote 
the following complaint : "Let us suppose that we all agree as to what 
wine is the best, how shall we get it? Our very princes do not drink 
pure wine ; to such a point has the villainy of the producers and sellers 
of wine arrived that we can buy nothing more than the name of a 
vintage — from the very wine-vat it is all adulterated — and so, marvellous 
to tell, we may say of wine, the poorer, the purer." 



68. What is paid of purity us a commercial term ? 



116 FOOD AND DRINK 

QUESTIONS FOR TOPICAL REVIEW 

PAGE 

1. How is the necessity for food shown ? s 91 

2. To what process of waste and repair is the body constantly subjected ? 91, 92 

3. How do you account for the sensations of hunger and thirst? 92, 93 

4. What further can you state having relation to the subject? 92 

5. What can you state in regard to the quantity of food required for 

the support of life ? 93, 94 

6. What circumstances change the needs of persons, old and young, as 

regards food and drink ? 93 

7. What becomes of all the food and drink we consume ? 95 

8. What further can you state in relation to the process of renovation 

through which the body passes ? 95 

9. What can you state of the habit of nations in respect to diet ? 95, 96 

10. What in relation to the selection of articles for food ? 96 

11. What has been proved as regards animal food ? 96 

12. What as respects the necessity for changing or varying the diet ? . . 96, 97 

13. Of what importance is milk as an article of food ? 97, 98 

14. What are the constituents of milk ? 98 

15. What can you state of eggs as an article of food ? 98 

16. Of the meats, so called, as an article of food ? .- 98 

17. What effect does cold have upon meats ? 99 

18. In what other way may beef and pork be preserved ? 99 

19. What can you state of salted meat as food, and of its continued use ? 99 

20. What change does meat undergo in the cooking ? 99-101 

21. What directions are given for boiling meat ? 100 

22. What for roasting, and with what results ? 100, 101 

23. What is said about the frying of meats ? 101 

24. Give the statement in relation to trichina 101 

25. State what is said in relation to fish 101 

26. What is stated of the usefulness and other properties of the prod- 

ucts of the vegetable kingdom ? 101, 102 

27. What further is said of vegetable food ? 101, 102 

28. Why is bread made of wheat-flour so important as an article of food ? 102 

29. State whatever else you can in relation to bread 102, 103 

30. Give the statement respecting the potato 103, 104 

31. What is stated of fruits, the use of them, their nutritious qualities, 

etc. ? 104 

32. How general is the existence of perfectly pure water? 104, 105 

33. What is stated in relation to drinking water ? 105 

34. What effect has the action of water upon lead ? 105, 106 

35. What further can you state on the subject ? 106 

36. What properties has coffee as an article of diet? 106, 107 

37. In what circumstance has coffee been found peculiarly beneficial?. 107 

38. What comparison is made between coffee, tea, and chocolate ? . . . 107, 108 

39. How are the wines, and malt, and other alcoholic beverages pro- 

duced ? 108, 109 

40. What articles are employed in their production ? 109 

41. What are the properties of alcohol ? 109 

42. Is alcohol a food ? 109, 110 

43. What is said of the property of alcohol to relieve thirst? 110 

44. What effect does alcohol have upon the body's temperature? .... 110, 111 

45. What is the cause for flushing of face in drinkers ? Ill 

46. What is the testimony of Arctic explorers and others? Ill 

47. What is the effect of alcohol upon plant and animal life ? 112 

48. What are the only conditions for use of alcohol ? 112 



CHAPTER VI 

DIGESTION 

The Principal Processes of Nutrition — The General Plan of Digestion 
— Mastication — The Teeth — Preservation of the Teeth — Action of 
the Saliva — The Stomach and the Gastric Juice — The Movements of 
the Stomach — Gastric Digestion — The Intestines — The Bile and 
Pancreatic Juice — Intestinal Digestion — Absorption by Means of 
Blood-vessels and Lacteals — The Lymphatic or Absorbent System — 
The Lymph — Conditions which affect Digestion — The Quality, Quan- 
tity, and Temperature of the Food — The Influence of Exercise and 
Sleep — The Kidneys — The Spleen — Effect of Alcohol on Digestion, 
the Liver, and Kidneys 

1. Nutrition. — The great design of food is to give nutriment 
or nourishment to the body. But this is not accompli shed 
directly, as the food must first pass through certain preparatory 
changes, as follows : (1), Digestion, by which the food is reduced 
to a soluble condition; (2), Absorption, by which, when digested, 
it is taken into the blood; (8), Circulation, which carries the 
enriched blood to the various parts of the system; and (4\ 
Assimilation, by which each tissue selects from the Mood the 
materials necessary for its support. 



1. Design of food ? How accomplished? 

117 



118 DIGESTION 

2. By these four steps the sustaining power of food is gradu- 
ally brought into exercise and the vital machinery kept in 
working order, somewhat after the manner of the steam-engine! 
To operate the latter, the force imprisoned within the coal and 
water is set free and converted into motion by the burning 
of the fuel and the vaporization of the water. It will be seen, 
however, when we come to study these operations in the human 
body, that they are conducted silently and harmoniously, with 
marvellous delicacy and completeness, and without that friction, 
and consequent loss of power, which attend the working of 
the most perfect machinery of man's invention. 

3. Glands. — Situated in all parts of the body are certain 
organs, called glands, which aid the work of nutrition in its 
various stages. Each gland consists of many active cells, all 
alike in general structure and function. These cells may be 
compared to the skilled laborers in a large factory. Like 
these, the cells take the "raw material," as it conies to them 
through the blood and lymph, separate it, and excrete on their 
free surface the finished product. This general process is 
called secretion. 

4. The product of the salivary glands is called saliva, that 
of the liver is called bile, that of the lachrymal glands is 
called tears, and so on. It is evident that if much material 
is to be secreted by a gland, many working cells are neces- 
sary. In order that many cells may be brought into as small 
a space as is possible, they are arranged on the surface of a 
tube or sack. Glands are of two types, tubular and racemose. 
If the general plan of arrangement is tha£ of a tube, either 
simple or compound, the gland is called a tubular gland. 
The perspiratory glands are good examples of this type. If 
the cells are arranged along a surface which swells out at 
its upper end, like a sack, the gland is called sacular or race- 
mose. The sebaceous glands are racemose. Either type may 
be simple or compound. 

2. Sustaining power of food ? Simile of the engine ? Operation in the human body ? 

3. Use of glands ? Constitution ? What is the process of secretion ? 

4. What is the product of the salivary glands called ? Of the liver ? Of the lachrymal 
glands ? Name the two types of glands. 



DIGESTION 



119 



5. General Plan of Digestion. — The great change which food 
undergoes in digestion is essentially a refining process, re- 
ducing articles of diet, which are at first more or less solid, 
crude, and coarse, to a liquid and finely comminuted condition, 

suitable for absorption into the blood. 
The entire process of digestion takes 
place in what is called the " alimen- 
tary canal," a narrow, crooked tube, 
about thirty feet in its entire length. 
This canal begins in the mouth, ex- 
tends thence downward through the 
gullet to the stomach (a receptacle in 
which the principal work of digestion 
is performed), and thence onward 
through the small and large intes- 
tines. 

6. The stomach and intestines are 
situated in the cavity of the abdomen 
(Fig. 22, C, and Fig. 28), and occupy 
about two-thirds of its space. The 
action to which the food is subjected 
in these organs is of two kinds — 
mechanical and chemical. By the 
former it is softened, agitated, and 
carried onward from one point to 
another ; by the latter it is changed 
in form through the solvent power of 




Fig. 22. — Section of the Trunk, 
showing the cavities op the 
Chest and Abdomen 

A, Chest C, Abdomen 

B, Diaphragm 1), Spinal Column 

E, Spinal Cord 



the various digestive fluids. 



7. Mastication. — As soon as solid 
food is taken into the mouth, it undergoes mastication or 
chewing. It is caught between the opposite surfaces of the 
teeth, and by them is cut and crushed into very small frag- 
ments. In the movements of chewing, the lower jaw plays 
the chief part; the upper jaw, having almost no motion, acts 



5. Change of food Indigestion? Process of digestion ? Describe the aliinentnrj canal. 

6. Situation of the stomach ami intestines'? Action of the food? Mechanical action? 
Chemical ? 

7. Describe the process of mastication, llow many and what movements? 



120 



DIGESTION 



simply as a point of resistance, to meet the action of the 
former. These movements of the lower jaw are of three 
sorts : an up-and-down or cutting, a lateral or grinding, and 
a to-and-fro or gnawing motion. 

8. The teeth are composed of a bone-like material called 
dentine, and are held in place by roots running deep into the 

jaw. The exposed portion, or 
" crown," is protected by a thin 
layer of enamel (Fig. 23, a), the 
hardest substance in the body, 
and, like flint, is capable of 
striking fire with steel. In the 
interior of each tooth is a cavity, 
containing blood-vessels and a 
nerve, which enter it through a 
minute opening at the point of 
the root (Fig. 25). 

9. There are two sets of 
teeth : first, those belonging to 
the earlier years of childhood, 
called the milk teeth, which 
are twenty in number and small. 
At six or eight years of age, 
when the jaw expands, and 
when the growing body requires 
a more powerful and numerous 
set, the roots of the milk teeth 
are absorbed, and the latter are " shed/' or fall out, one after 
another (Fig. 24), to make room for the permanent set. 

10. There are thirty-two teeth in the permanent set, an 
equal number in each jaw. Each half-jaw has eight teeth, 
similarly shaped and arranged in the same order ; thus, two 
incisors, one canine, two bicuspids, and three molars. The 
front teeth are small, sharp, and chisel-edged, and are well 
adapted for cutting purposes ; hence their name incisors. The 




Fig. 23. — Section of a Tooth 

a, Enamel ; b, Cavity ; c, c, Roots ; 

d, Body of the Tooth 



8. Composition of the teeth ? Enamel of the teeth ? Interior of the teeth 

9. The milk teeth ? The permanent teeth ? 

10, 11. The number of the teeth ? How arranged ? 



DIGESTION 



121 



canines stand next, one on each side of the jaw; these receive 
their name from their resemblance to the long, pointed tusks 
of the dog (Fig. 25). 

11. The bicuspids, next in order, are larger and have a 
broader crown than the former; while behind them are the 
molars, the largest and most powerful of the entire set. These 




Fig. 24.- 
1'2'3'4'5\ The Milk Teeth 



■Section of the Jaws 
1" to 8". The Germs of the Permanent Set 



large back teeth, or " grinders," present a broad, rough surface, 
suitable for holding and crushing the food. The third molar, 
or " wisdom tooth," is the last to be cut, and does not appear 
until about the twenty-first year. The arrangement of the 
teeth is indicated by the following dental formula. : 




122 



DiGusrioir 



12. It is interesting, at this point, to notice the different 
forms of teeth in different animals, and observe how admirably 
their teeth are suited to the respective kinds of food upon 
which they feed. In the carnivora, or flesh-feeders, the teeth 
are sharp and pointed, enabling them both to seize their prey 




Fig. 25. — Section of the Jaws — Eight Side 
V, A, "N, Veins, Arteries, and Nerves of the Teeth. The root of one tooth in each jaw is 
cut vertically to show the cavity and the blood-vessels, etc., within it. 1 to S, Perma- 
nent Teeth 

and tear it in pieces ; while the herbivora, or vegetable-feeders, 
have broad, blunt teeth, with rough crowns, suitable for grind- 
ing the tough grasses and grains upon which they feed. 

12, Different forms of teeth? Human teeth? The inference? 



DIGESTION 123 

Human teeth, partake of both forms; some of them are sharp, 
and others are blunt ; they are therefore well adapted for the 
mastication of both flesh and vegetables. Hence we infer 
that, although man may live exclusively upon either vegetable 
or animal food, he should, when possible, choose a diet made 
up of both v?,rieties. 

13. Preservation of the Teeth. — In order that the teeth shall 
remain in a sound and serviceable condition, some care is of 
course requisite. In the first place, they require frequent 
cleansing; for every time we take food, some particles of it 
remain in the mouth, and these, on account of the heat and 
moisture present, soon begin to putrefy. This not only ren- 
ders the breath very offensive, but promotes decay of the teeth. 

14. The saliva, or moisture of the mouth, undergoes a 
putrefactive change, and becomes the fertile soil in which a 
certain minute fungus has its growth. This fluid, too, if 
allowed to dry in the mouth, collects upon the teeth in the 
form of an unsightly, yellow concretion, called tartar. To 

^prevent this formation, and to remove other offensive sub- 
stances, the teeth should be frequently cleaned with water, 
applied by means of a soft tooth-brush. The prevention of 
the tartar fungus is best effected by the use of a weak solution 
of carbolic acid. (Read Note 1.) 

1. The Proper Care of the Teeth. — tl It is an important question how 
to care for the molars. To this end the cardinal maxim is cleanliness; 
and again cleanliness. One means of cleansing is the natural one — that 
is, by chewing food ; for it is well known that if we have a tooth so situ- 
ated in the jaw that it is seldom brought into use, that tooth early shows 
signs of decay. But' more effectual is the artificial means — the brush. 
Children should early be taught to use this ; and for them a softer brush 
should be selected than for adults. They should also early be taught to 
use no metallic substances, as pins, needles, etc., to remove substances 
from between the teeth. The teeth should always be thoroughly cleansed 
after taking acids into the mouth — for they are the great enemies to the 
teeth — and also after candies and other forms of sugar, for their particles 
that linger on the teeth are changed by decomposition into laetie arid. 
Occasional examination of the teeth is prudent, in order that a com- 
mencing cavity may be promptly detected ami remedied. Teeth that are 



L8, Cleaning of teeth? Effiectsofnol cleaning? 

14. Effects of the saliva? Formation of tartar? How prevented I Hov desti 



124 DIGESTION 

15. It should be borne in mind that the enamel, Nature's 
protection for the teeth, when once destroyed, is never formed 
anew ; and the body of the tooth thus exposed is liable to rapid 
decay. On this account, certain articles are to be guarded 
against ; such as sharply acid substances that corrode the 
enamel, and hard substances that break or scratch it — as 
gritty tooth-powders, metal tooth-picks, and the shells of hard 
nuts. Sudden alterations from heat to cold, when eating or 
drinking, also tend to crack the enamel. 

16. Action of the Saliva. — While the morsel of food is cut 
and ground by the teeth, it is at the same time intimately 

mixed with the saliva, or 
fluids of the mouth. This 
constitutes the second step 
of digestion, and is called 
insalivation. The saliva, 
the first of the digestive 
solvents, is a colorless, 
watery, and frothy fluid. 
It is secreted (i.e., sepa- 
rated from the blood) 
partly by the mucous 
membrane which lines the 

Fig. 26. — Structure of a Salivary Gland 

mouth, but chiefly by the 
salivary glands situated near the mouth. 

17. The parotid glands lie below and in front of the ear. 
Mumps is an inflammation of these glands. Each opens by a 
duct into the mouth near the second upper molar tooth. The 
submaxillary glands, are situated near the angles of the lower 
jaw, at the base of the tongue. They have a single duct which 
opens into the mouth beneath the tongue. The sublingual 
glands are the smallest of the three pairs, and lie just beneath 
the forward end of the tongue. ' They open into the floor of 
the mouth by several ducts. 

decayed beyond the remedy by filling should be immediately removed." 
— Lane on the Hygiene of the Teeth. 




15. Care of enamel ? 16. What is saliva ? 17. Name four kinds of glands. 




DIGESTION 125 

18. These glands consist of clusters of very small pouches, 
around which a delicate network of blood-vessels is arranged ; 
they empty into the mouth by means of little tubes, or ducts. 
The flow from these glands is generally sufficient to maintain 
a soft and moist condition of the tongue and mouth ; but when 

they are excited by the pres- 
ence and taste of food, they 
pour forth the saliva more 
freely. Even the mere thought 
of food will at times cause the 
saliva to flow, as when the ap- 
petite is stimulated by the 
sight or smell of some savory 
article; so that the common 
expression is correct that " the 
mouth waters " for the favorite 

Fig. 27. — The Head of a Horse, showing articles of food. Anxiety and 
the large salivary gland (a) , its duct (6) the ■ f prevent its flow and 
muscles of mastication (c, d, e, f, and g) & r ' 

cause " the tongue to cleave to 
the roof of the mouth." In the horse, and other animals that 
feed upon dry and coarse fodder, and require an abundant 
supply of saliva, we find large salivary glands, as well as 
powerful muscles of mastication. 

19. The mingling of the saliva with the food seems a simple 
process, but it is one that plays an important part in digestion. 
In the first place, it facilitates the motions of mastication, by 
moistening the food and lubricating the various organs of the 
mouth. Secondly, it prepares the way for other digestive 
acts : by the action of the teeth, the saliva is forced into the 
solid food, softens the harder substances, and assists in con- 
verting the whole morsel into a semi-solid, pulpy mass, that 
can be easily swallowed, and readily acted upon by other 
digestive fluids. The saliva, also, by dissolving certain sub- 
stances, as sugar and salt, develops the peculiar taste of eaeh ; 
whereas, if the tongue be dried and coated, they are taste- 
is. The flow of saliva ? The thought of food ? Anxiety and grief? Animals fed upon 
dry and coarse food ? 

Vj), Importance of the pvowflsj TneflrstpUweS TheseoondJ The third, 5 



126 DIGESTION 

less. Hence, if substances are insoluble, they are devoid of 
taste. 

20. Finally, the saliva has the property of acting chemically 
upon the food. As we have before stated (Chap. IV.), starch, 
as starch, cannot enter the tissues of the body ; but, in order to 
become nutriment, must first be changed to grape-sugar. This 
change is, in part, effected by the saliva, and takes place almost 
instantly, whenever it comes in contact with cooked starch. 
This important function is due to an organic ingredient of the 
saliva called ptyalin. This substance has been extracted from 
the saliva by the chemist, and has been found, by experiment, 
to convert into sugar two thousand times its own weight of 
starch. (Bead Notes 2 and 3.) % 

2. The First Step of Digestion. — "The digestive process begins in 
the mouth ; among civilized people it begins in the plate, or even before. 
Undoubtedly mastication is the natural method of mincing meat, and not 
the least of its value lies in the fact that it takes time. A man who is 
eating a tough, and therefore not very digestible chop, will be slow in 
eating, if he is careful to masticate it well. There will be a long interval 
between each mouthful, and the stomach will run no risk of being hastily 
loaded. 

" Now, a hastily-loaded stomach is as bad almost as, or, rather, is the 
same thing as, an overloaded stomach ; and there can be no doubt that 
artificial mastication becomes a snare when it leads any one to introduce 
a large quantity of finely-minced meat suddenly and rapidly into an 
unprepared stomach, especially into the feeble stomach of an invalid, 
under the idea that, because the meat is so nicely minced, and so very 
tender, it can be no possible burden to that sorely-tried organ. Natural 
mastication has, besides, another advantage over the artificial process, 
which is perhaps not always recognized. Whenever food enters the 
mouth, it gives rise to what is called a flow of saliva. This saliva is 
secreted by certain glands, which pour into the mouth the fluid they 
strain off from the blood, and which are excited or stimulated to action 
by the presence of food in the mouth, as well as by other causes. Saliva 
rapidly changes starch into sugar, and sugar is pre-eminently a soluble 
body, passing with the greatest ease from the alimentary canal into the 
blood." — People's Magazine (London). 

3. Experiment. Saliva. — The chemical action of saliva upon boiled 
starch may be demonstrated by the following simple experiments : 

1. Trepare a thin solution of boiled starch; three parts of starch to, 
one hundred parts of water j boil for a few minutes. 



20, Its final importance ? Starch? How effected? Ptyalin? 



DIGESTION 127 

21. Importance of Mastication and Insalivation. — Each, of 

these processes complements the other, and makes the entire 
work available; for, by their joint action, they prepare the 
food in the best possible manner for further digestive changes. 
The study of these preliminary functions will appear the more 
important, when we reflect that they are the only ones which 
we can regulate by the will. For, as soon as the act of swallow- 
ing begins, the food not only passes out of sight, but beyond 
control; and the subsequent acts of digestion are consequently 
involuntary and unconsciously performed. 

22. It is generally known that rapid eating interferes with 
digestion. How does this occur ? In the first place, in rapid 
eating, the flow of the saliva is insufficient to moisten the solid 
parts of the food, so that they remain too hard and dry to be 
easily swallowed. This leads to the free and frequent use of 
water, or some other beverage, at meals, to "wash down" the 
food — a most pernicious practice. For these fluids not only 

2. Obtain a fresh quantity of saliva, which is best done by revolving 
a small pebble in the mouth, which causes a copious flow. Collect this 
in a separate vessel. 

3. Demonstrate that no sugar is present in this starch solution. 
Obtain from a druggist an ounce or two of " Fehling's solution" (this 
is a solution of sulphate of copper and of certain alkalies). Sugar has 
the power of changing the sulphate into an oxide of copper which is red- 
dish-brown. Of this put half a teaspoonful into a test-tube, add an equal 
quantity of the starch solution, and let it come to a boil over an alcohol 
lamp. No change in the blue color will be observed. 

4. Demonstrate that the saliva does not contain sugar by bailing a 
small quantity with an equal quantity of "Fehling's solution," when no 
change of the blue color will be observed. 

5. Now in a third test-tube mix a quantity of the starch solution with 
one-third its volume of fresh saliva, and set aside for five to ten minutes 
in a warm place, or a glass of warm water of about 100° F. Then take 
of this again a small quantity and add an equal part of u Fehling's solu- 
tion," shake the mixture and boil. As soon as the boiling point is 
approached, it will be seen that the blue color disappears, being replaced 
by a reddish-brown color. This demonstrates the presence o( sugar in 
the starch solution, produced by the action of the saliva added. 

21. Each of the processes? Why is a knowledge of the digestive Functions important ? 
How shown ? 

•J2. Rapid eating? Describe the process and effects. 



128 DIGESTION 

cannot take the place of the natural digestive juices, but, on 
the contrary, dilute and weaken them. 

23. Secondly, the saliva being largely the medium of the 
sense of taste, the natural flavors of the food are not devel- 
oped, and consequently it appears comparatively insipid. 
Hence the desire for highly-seasoned food, and pungent 
sauces, that both deprave the taste and over-excite the diges- 
tive organs. Eapid eating also permits the entrance of injuri- 
ous substances which may escape detection by the taste, and 
be unconsciously'received into the system. In some instances, 
the most acrid and poisonous substances have been swallowed 
" by mistake," before the sense of taste could act and demand 
their rejection. 

24. Thirdly, the food, being imperfectly broken up by the 
teeth, is hurried onward to the stomach, to be by it more 
thoroughly divided. But the stomach is not at all adapted to 
perform the task thus imposed upon it ; and the crude masses 
of food remain a heavy burden within the stomach, and a 
source of distress to that organ, retarding the performance 
of its proper duty. Hence persons who habitually eat too 
rapidly, frequently fall victims to dyspepsia.* Eapid eating 
also conduces to overeating. The food is introduced so 
rapidly that the system has not time to recognize that its 
real wants are met, and hence the appetite continues, although 
more nutriment has been swallowed than the system requires, 
or can healthfully appropriate. 

25. The Stomach. — As soon as each separate portion of food 
is masticated and insalivated, it is swallowed; that is, it is 
caused to move downward to the stomach, through a narrow 
muscular tube about nine inches in length, called the cesophar 
gus, or gullet (Fig. 29). The stomach is the only large expan- 

* For the same reason, persons who prematurely lose their teeth suffer 
from dyspepsia. For them a proper means of relief is the use of artificial 
teeth. 

23. Loss of taste ? Another effect of rapid eating ? Mistakes ? 

24. Effect of imperfectly-broken food in the stomach ? Dyspepsia ? Overeating? 

25. Gullet ? Describe the stomach and its location. Effects of gormandizing ? 



DIGESTION 



129 



sion of the digestive canal, and is a most important organ 
of digestion. It is a hollow, pear-shaped pouch, having 

a capacity of three pints, 
in the adult. Its walls 
are thin and yielding, and 
may become unnaturally 
distended, as in the case 
of those who subsist on 
a bulky, innutritious diet, 
and of those who habit- 
ually gormandize. 

26. The stomach has 
also two openings; that 
by which food enters, 
being situated near the 
heart, is called the car- 
diac, or heart orifice ; the 
other is the pylorus, or 
"gatekeeper," which 
guards the entrance to the 
intestines, and, under ordi- 
nary circumstances, per- 
mits only such matters to 
pass it as have first been 
properly acted- upon in the 
stomach. Coins, buttons, and the like are, however, readily 
allowed to pass, because they can be of no use if retained. 
The soft and yielding texture of this organ — the stomach — 
indicates that it is not designed to crush and break up solid 
articles of food. 

27. The Gastric Juice. — We have seen how the presence of 
food in the mouth excites the salivary glands, quickly causing 
the saliva to flow. In the same manner, when food reaches 
the stomach, its inner lining, the mucous membrane, is at 




Fig. 28. — Section of Chest and Abdomen 

A, Heart E, Gall Bladder 

B, The Lungs F, Stomach 

C, Diaphragm G, Small Intestine 

D, The Liver H, Large Intestine 



26. Heart orifice? Gatekeeper? Coins 
ure of the stomach ? 

27. What is meant by the gastric juice ? 



indication of the soft and yielding text- 



130 



DIGESTION 



once excited to activity. At first, its surface, which while 
the stomach is empty presents a 
pale pink hue, turns to a bright red 
color, for the minute blood-vessels 
which course through it are filled 
with blood. Presently a clear, color- 
less, and acid fluid exudes, drop by 
drop, from millions of little tubes in 
the inner surface of the stomach, 
until finally the surface is moistened 
in every part, and the fluid begins to 
mingle with the food. This fluid is 
termed the gastric juice. 

28. The gastric juice dissolves cer- 
tain articles of food, especially those 
belonging to the albuminoid class. 
This solvent power is due to its 
peculiar ingredient, pepsin; in diges- 
tion, this substance acts like a fer- 
ment — that is, it induces changes in 
the food simply by its presence, but 
does not itself undergo change. The 
acidity of the gastric juice, which is 
due to hydrochloric acid, is not acci- 
dental; for we find that the pepsin 
cannot act in an alkaline solution — 
that is, one which is not acid or neu- 
tral. The quantity of gastric juice 
secreted daily is very large, probably 
not less than three or four pints at 
each meal. Though this fluid is at 
once used in the digestion of the 

food, it is not lost ; since it is soon re-absorbed by the stomach, 
together with those parts of the food which it has digested and 
holds in solution. 




Fig. 29. Alimentary Canal — in- 
cluding Gullet, Stomach, Small 
and Large Intestines 



28. What is the office of the gastric juice ? Acidity of the gastric juice ! 
gastric juice used ? What becomes of it ? 



Quantity ot 



DIGESTION 131 

29. Movements of the Stomach. — The inner coating of the 
stomach is the mucous membrane, which, as we have seen, 
furnishes the gastric juice. Next to this coating lies another, 
called the muscular coat, composed of involuntary muscular 
fibres, some of which run circularly, and others in a longitudinal 
direction. These expand to accommodate the food as it is intro- 
duced, and contract as it passes out. In addition, these fibres 
are in continual motion while food remains in the stomach, 
and they act in such manner that the contents are gently 
turned round from side to side, or from one end of it to the 
other. 

30. By these incessant movements of the stomach, called 
the peristaltic movements, the gastric juice comes in contact 
with all parts of the food. We are, however, not conscious 
that these movements take place, nor have we the power to 
control them. When such portions of the food as are suffi- 
ciently digested approach the pylorus, it expands to allow them 
to pass out, and it closes again to confine the residue for further 
preparation. 

31 . The knowledge of these and other interesting and instruc- 
tive facts has been obtained by actual observation ; the work- 
ings of the stomach of a living human being have been laid 
open to view and examined — the result of a remarkable acci- 
dent. Alexis St. Martin, a Canadian voyageur, received a gun- 
shot wound which laid open his stomach, and which, in healing, 
left a permanent orifice nearly an inch in diameter. Through 
this opening the observer could watch the progress of digestion, 
and experiment with different articles of food. Since that 
occurrence, artificial openings into the stomach of the inferior 
animals have been repeatedly made, so that the facts of stomach- 
digestion are very well ascertained and verified. (Bead Note 4.) 

4. The Digestibility of Solid Foods. — "The accompanying table 

shows some of the results obtained from the experiments of Dr. Beaumont 



29. Muscular coat of tbo stomach? Expansion ami contraction of its fibres? Action 
of the fibres ? 

80. Peristaltic movements ? What is said of our consciousness o\' and power over those 
movements ? Describe the movement of the pylorus. 

81. How has the knowledge and the workings of the stomach boon ascertained * St, 
Martin ? How else ? 



132 



DIGESTION' 



32. Gastric Digestion. — What portions of the food are 
digested in the stomach ? It was formerly thought that all 
the great changes of digestion were wrought here, but later 
investigation has taught us better. We now know that the 
first change in digestion takes place in the mouth, by the partial 
conversion of starch into sugar. We also know that, of the 
three organic food principles (considered in Chap. IV.) two 
— the fats and the sugars — are but slightly affected by the 
stomach ; but that its action is confined to that third and very 
important class from which the flesh is formed, the albuminoids. 
A few articles need no preparation before entering the system, 
as water, salt, and fruit-sugar. These are rapidly taken up 
by the blood-vessels of the stomach, which everywhere underlie 
its mucous membrane in an intricate and most delicate network. 
In this way the function of absorption begins. 



upon the stomach of Alexis St. Martin. It will surprise many to find that 
vegetable foods — they are placed in the latter part of the table — require 
so long a time for their digestion." 



Time re- 

v •> Mode of quired for 

• rooQ - Cooking, digestion. 

h. m. 

Pork roasted 5 15 

Cartilage boiled 4 15 

.4 
.4 
.4 
.4 
.3 30 
.3 30 



Ducks roasted . . . 

Fowls do. 

Do boiled 

Beef fried 

Eggs do 

Do hard boiled 

Cheese 

Oysters stewed 

Mutton roasted 

Do boiled 



.3 30 
.3 30 
.3 15 
.3 

Beef roasted 3 

Do boiled 2 45 

Chicken ...,,..,,.,,,.., .fricasseed . , .2 45 

Lamb ,,..,,...,. r ._ .broiled.. ... .2 30 

Pig (suckling) ........... .roasted 2 30 

Goose do 2 30 

Gelatin boiled 2 30 

Turkey do 2 25 

Eggs roasted 2 15 

Cod Fish (cured, dry) boiled 2 

Ox Liver broiled 2 

Venison Steak do 130 



Food. 



Time re- 
Mode of quired for 
Cooking, digestion 
h. m. 

Salmon Trout boiled 1 30 

Eggs (whipped) raw 1 30 

Tripe (soused) boiled 1 

Pig's Feet (soused) do 1 

Cabbage boiled 4 

Beetroot do 3 45 

Turnips do 3 30 

Potatoes do 3 30 

Wheaten Bread baked 3 30 

Carrots boiled 3 15 

Indian Corn Bread baked 3 15 

Do. Cake do 3 

Apple-dumpling boiled 3 

Potatoes baked. 2 33 

Do roasted 2 30 

Parsnips boiled 2 30 

Sponge Cake. ..,,., baked 2 30 

Beans foiled 2 30 

Apples (sour) raw 2 

Barley boiled 2 

Tapioca do. ... 2 Q 

Sago do. ....... 1 45, 

Apples (sweet) .-raw t 30 

Eice boiled 1 Q 



32. What was formerly thought ? What do j we now know ? 
fcnow ? Water, salt, and sugar ? Absorption ? 



What else do we now- 



DIGESTION 133 

33. The albuminoid substances are speedily attacked and 
digested by the gastric juice. From whatever source they are 
derived, vegetable or animal, they are all transformed into the 
same digestive product, called peptone. This is very soluble 
in water, and is in part absorbed by the blood-vessels of the 
stomach. After a longer or shorter time, varying from one to 
five hours, according to the individual and the quantity and 
quality of his food, the stomach will be found empty. Not 
only the unabsorbed digested food, but also those substances 
which the stomach could not digest, have passed little by little 
through the pylorus, to undergo further action in the intestines. 
At the time of its exit the digested food is of a pulpy con- 
sistence, and dark color, and is then known as the chyme. 
{Bead Notes 5 and 6.) 

5. Indigestible Matters. — "Children sometimes swallow coins, but- 
tons, etc., and so cause great alarm. There is little real ground for appre- 
hension under these circumstances, unless the coins are bronze. If the 
latter, there is some cause for fear that copper poisoning will ensue, and 
the ready passage of the coin is desirable. This is best effected by meals 
of figs or pudding, in which the coins are imbedded, and so passed harm- 
lessly. As to bulk, whatever will go into the stomach will pass the 
various straits and emerge again." — Fothergill. 

6. Experiment. Gastric Juice. — The action of the gastric juice upon 
the albuminoids can be readily demonstrated outside of the body. For 
this it is necessary to prepare a solution of pepsin and a solution of hydro- 
chloric acid. The first of these may be made in one of two ways. The 
simplest of these is to obtain some pure pepsin from the druggist, and 
dissolve of this thirty grains in four ounces of pure glycerin ; the other, 
but more complicated way, is to obtain a pig's stomach, dissect off the 
mucous membrane, mince finely and add six ounces of glycerin, set aside 
for a week and strain through muslin. The solution of hydrochloric acid 
should be of the strength of two parts per thousand, which would be 
about two or three drops of the strong acid to four ounces of water. 

Demonstrate that neither the solution of pepsin nor the hydrochloric 
acid alone have the power to digest albuminoids. 
Prepare three test-tubes as follows : 

1. Into one put about a teaspoonful of the pepsin solution, and add a 
small piece of the white of a hard-boiled egg. 

2. Into the second test-tube put a teaspoonful of the dilute hydro- 
chloric acid, and add again a small piece of the white of the egg. 

3. The third test-tube fill half with the solution of acid, add half a tea- 
spoonful of the pepsin solution, and again a small piece of the egg. 



::;;. Albuminose? The process? Chyme? 



134 DIGESTION 

34. The Intestines. — The intestines are continuous with the 
stomach, and consist of a fleshy tube, or -canal, twenty-five feet 
in length. The small intestine, whose diameter is about one 
inch and a half, is twenty feet long, and very winding. The 
large intestine is much wider than the former, and five feet 
long (Fig. 29). The general structure of these organs resembles 
that of the stomach. Like it, they are provided with a mucous 
membrane, or inner lining, whence flow their digestive juices ; 
and, just outside of this, a muscular coat, which propels the 
food onward from one point to another. 

35. Moreover, both the intestines and stomach are enveloped 
in the folds of the same outer tunic or membrane, called the 
peritoneum. This is so smooth and so well lubricated, that 
the intestines have the utmost freedom of motion within 
the abdomen. In the small intestines the work of digestion is 
completed, the large intestine receiving from them the indi- 
gestible residue of the food, and in time expelling it from the 
body. 

36. Intestinal Digestion. — As soon as the food passes the 
pylorus and begins to accumulate in the upper part of the 
intestines, it excites the flo^w of a new digestive fluid, which 
enters through a small tube, or duct, about three inches below 
the stomach. It is formed by the union of two distinct fluids 
— the bile and the pancreatic juice. The bile is secreted by the 
cells of the liver, the largest gland of the body, situated on 
the right side and upper part of the abdomen (Fig. 28). The 
bile is constantly formed, but it flows most rapidly during 
digestion. During the intervals of digestion it is stored in the 
gall-bladder, a small membranous bag attached to the under 



Now set these three tubes aside in a warm place for a few hours, or 
until the following day, when you will be able to demonstrate that in the 
first two no change has taken place, while the white of egg in the third 
has been entirely dissolved. 



34. What are the intestines ? The small intestines? The large intestines? Their 
structure ? 

35. Peritoneum? The work of digestion ? 

36. The presence of food in the intestines ? Bile ? ( 



DIGESTION 135 

side of the liver. This fluid is of a greenish-yellow color, hav- 
ing a peculiar smell, and a very bitter taste ; its exact part in 
the process of digestion is not known. That it is an impor- 
tant one, cannot be doubted. For if its proper flow into the 
intestinal canal is interfered with, or stopped, serious illness 
is the result. Its chief function seems to be to aid in the 
digestion of fats, by emulsifying them ; it also acts as a disin- 
fectant of the intestinal tract, increases the muscular contrac- 
tions of the intestines, and aids in a general way, in the 
absorption of the products of digestion. {Read Note 7.) 

37. The pancreatic juice is the product of a gland called the 
pancreas, situated behind the stomach. This fluid is colorless, 
watery, alkaline, and without odor. Like the digestive juices 
previously described, it owes its solvent power to its peculiar 
ferments. The most important of these ferments, called pan- 
creatin, transforms starch into sugar. Another, trypsin, causes 
the solution of undissolved albuminoid substances ; and a third 
ferment, which has not received a name, causes a partial acidi- 
fication of the fats. By the joint action of these fluids, the 
food is prepared for absorption. There results from this action 
of the pancreatic juice a white and milky fluid, termed the 
chyle, which holds in solution the digestible portions of the 
food, and is spread over the extensive absorbent surface of 
the small intestines. (Read Note 8.) 

38. The mucous membrane of the intestines, also, secretes 

7. Experiment. Bile. — The chief function of the bile in the diges- 
tion of food is the emulsifying of fats. 

If a quantity of oil is shaken up with an equal part of water in a test- 
tube, the two will not mix. But if we substitute bile for the water, and 
shake thoroughly, we obtain an emulsion which will separate but slowly 
and imperfectly. 

The bile may be obtained from the gall-bladder of the ox or sheep at 
any butcher's or slaughter-house. 



:;7. What produces the pancreatic juice? 
Where is the pancreas situated ? 
Describe pancreatin. Trypsin, 

How is food prepared for absorption : J 

What is chyle ? What is its funotion 1 
How performed ? 



136 DIGESTION 

or produces a digestive fluid by means of numerous " follicles," 
or minute glands ; this is called the intestinal juice. From 
experiments on the lower animals, it has been ascertained that 
this fluid exerts a solvent influence over each of the three 
organic food principles, and in this way completes the action 
of the fluids previously mentioned, viz. : of the saliva in 
converting starch into sugar, of the gastric juice in digesting 
the albuminoids, and of the pancreatic' juice and bile in 
emulsifying the fats. 

39. The Large Intestine (or Colon) is joined to the small 
intestine at right angles to it, at some distance from its closed 
lower end. At this point of junction there is a valve, called 
the ileo-ccecal valve, which prevents the contents of the small 
intestine from passing back into the latter after they have once 
entered the large intestine. The closed lower end of the large 
intestine (called the caecum) ends in a slender tube from two to 
five inches in length, called the vermiform appendix, inflam- 
mation of which produces the disease known as appendicitis. 
From its beginning, the large intestine passes upward to the 
under surface of the liver, this portion being called the ascend- 
ing colon ; then it turns at right angles to the left, and across 
the abdominal cavity just below the stomach, until it reaches 
the left side of the abdomen, this portion being called the 
transverse colon ; from here it passes downward, forming the 
rectum. 

40. Absorption. — With the preparation of the chyle, the 
work of digestion is completed ; but it has not yet become a 
part of the blood, by means of which it is to reach the dif- 
ferent parts of the body. The process by which the liquefied 
food passes out of the alimentary canal into the blood is called 
absorption. This is accomplished in two ways : first, by the 



3S. What does the mucous membrane of the intestines secrete? What is it called? 
What influence does this fluid exert? The action of what other fluids is completed by the 
intestinal juice ? 

39. Where is the large intestine joined to the small intestine ? Where is the ileo-csecal 
valve ? What purpose does it serve ? What is the vermiform appendix ? What disease is 
produced by inflammation of the vermiform appendix ? Describe the course of the large 
intestine. 



DIGESTION 137 

blood-vessels. We have seen how the inner membrane of the 
stomach is underlaid by a tracery of minute and numerous 
vessels, and how some portions of the food are by them 
absorbed. The supply of blood-vessels to the intestines is 
even greater; particularly to the small intestines, where the 
work of absorption is most actively carried on. 

41. The absorbing surface of the small intestines, if con- 
sidered as a plane surface, amounts to not less than half a 
square yard. Besides, the mucous membrane is formed in 
folds with an immense number of thread-like prolongations, 
called villi, which indefinitely multiply its absorbing capacity. 
These villi give the surface the appearance and smoothness of 
velvet, and during digestion they dip into the canal, and, by 



8. Experiment. Pancreatic Juice. — To obtain the pancreatic juice, 
it will be necessary to extract it from a fresh pancreas, " sweet-bread" 
(which may be bought of any butcher), by means of either water or 
glycerin. Mince the pancreas finely and add sufficient of either of these 
liquids to cover it, set aside for a day and strain or filter. The glycerin 
extract will keep for a long time ; the watery extract soon spoils. 

The pancreatic juice has a digestive action on all the food-stuffs. 

Its action upon boiled starch may be demonstrated by repeating the 
experiments detailed under " Saliva," only substituting the extract of the 
pancreas for the saliva. 

Its action upon albuminoids is shown by adding to a few teaspoonfuls 
of the pancreatic extract some finely minced meat, or a part of the 
white of a boiled egg. But as the action of the pancreatic juice can 
only proceed in an alkaline medium, it is necessary to be certain of the 
alkalinity of the fluid. This is best done by adding about five grains of 
carbonate of soda (washing soda) to each ounce of pancreatic extract. 
Set the test-tube aside in a warm place for a few hours, when the meat 
or white of egg will be found entirely dissolved. 

Its action upon fats may be shown by shaking up in a test-tube a 
quantity of the extract with an equal part of melted lard or oil, when 
we will obtain a very perfect emulsion. 



40. What completes the work of digestion ? How much thus far has boon done with the 
food ? What remains to he done? What is this process called ? In what two ways is it 
accomplished ? By what is the inner membrane of the stomach underlaid ? What purpose 
does it serve? Are the intestines supplied with corresponding blood-vessels? In greater 
or less quantity ? Where js the work of absorption most actively carried on ? 

-II. Considered as a plane surface, what is the extent of the absorbing surface of the 
small intestines? Describe the formation of the mucous membrane. What arc the \ illi ? 
In what way do the villi affect the surface of the membrane? What is their office during 

digestion ? 



138 



DIGESTION 



means of their blood-vessels, absorb its fluid contents, just as 
the spongioles which terminate the rootlets of plants imbibe 



moisture from the surrounding soil. 



42. Secondly, absorption is also effected by the lacteals, a 
set of vessels peculiar to the small intestines. These have 
their beginnings in the little villi just mentioned, side by side 
with the blood-vessels. These two sets of absorbents run in 



E C 




D B 

Fig. 80. —The Lacteals 
A, Small Intestine; B, Lacteals; C, Thorax Duct; D, Absorbents; E, Blood-vessel 

different courses, but their destination is the same, which is 
the right side of the heart. The lacteals receive their name 
from the milky-white appearance. After a meal containing 
a portion of fat, they are distended with chyle, which they 



42. How is absorption effected in another way ? Describe it. 
From what is the name of the lacteals derived ? 
What tube is formed by the union of the lacteals ? 
Describe its course. 



DIGESTION 139 

are specially adapted to receive ; at other times they are 
hardly discernible. The lacteals all unite to form one tube, 
the thoracic duct, which passes upward through the thorax, 
or chest, and empties into a large vein, situated just beneath 
the left collar-bone. 

43. The Absorbents. — The lacteals belong to a class of ves- 
sels known as absorbents, or lymphatics, which exist in nearly 
all parts of the body, except the brain and spinal chord. The 
fluid which circulates through the lymphatics of the limbs, 
and all the organs not concerned in digestion, is 'called lymph. 
This fluid is clear and colorless, like water, and thus differs 
from the milky chyle which the lacteals carry after digestion : 
it consists chiefly of the watery part of the blood, which was 
not required by the tissues, and is returned to the blood by 
the absorbents or lymphatics. {Read Note 9.) 

44. Osmosis is the name given to that process which enables 
two fluids, capable of being mixed, to pass through animal 
membrane, which separates them. This may be readily illus- 
trated by filling a glass tube half full with a strong salt solu- 
tion, and closing its open end by a piece of bladder or intestine, 
and then standing the tube, with the membrane downward, in 
a glass of water. After a while it will be noticed that the sur- 
rounding fresh water has become salty, and also that the fluid 
in the glass tube has increased in volume. Upon analyzing the 
two fluids now, we will find that more water has passed into 
the salt solution than salt into the water, showing that the 
lighter fluid (water) passes more readily into the denser fluid 
(salt solution). The more abundant passage of the water 
through the membrane to the salt is called endosmosis; and the 



43. To what class of vessels do the lacteals belong '? 

In what parts of the body are absorbents not found ? 

What fluid circulates through the lymphatics of the limbs S 

In what respect does it differ from the chyle carried by the lacteals after digestion ? 

Of what does it consist ? 

How is it returned to the blood ? , 

44. Describe the process of osmosis. 
How may it be Illustrated ? 

Describe the experiment. 

What is endosmosis ? Exosmosis ? 



140 DIGESTION . 

more scanty passage of the salt outward into the water is 
called exosmosis. (Read Note 9.) 

45. Dialysis. — Different substances will penetrate animal 
membrane with different degrees of rapidity. As a rule, crys- 
tallizable substances, such as mineral salts, glucose, or urea, 
pass with facility ; while non-cry stallizable, such as albumen, 
starch, or gum, pass through not at all, or with difficulty. The 
former substances are called diffusible, and the latter non- 
diffusible. This distinction is not absolute, however, for by 
increasing the pressure on one side of the membrane, nearly 
all soluble substances can be made to pass through to some 
degree. The separation of substances of different diffusibility 
from each other is called dialysis. To illustrate : If a mixture 
of sugar and gum, dissolved in water, be placed on one side of 
the membrane, and pure water on the other, it will be found 
that the sugar will pass through the membrane, while the gum 
will be left behind. It is by this process of dialysis that the 
products of digestion are separated from the waste and indi- 
gestible parts of food, and absorbed into the circulation. 

46. The absorption of the food, when it reaches the intes- 
tine in liquefied form, is as follows : all of it passes through the 
epithelial cells of the villi (see Fig. 31), and thence directly 
into both blood-vessels and lacteals ; peptones, water, salts, and 
glucose pass directly into the vessels and lacteals, and emulsi- 
fied fats after passing through the epithelial cells pass into 
the lacteals. Peptones, salts, water, and fats are taken from 
the blood by the tissues directly, while the glucose is carried 
through the portal circulation into the liver. This organ 
changes the glucose to a new substance, called glycogen, and 
stores it up in its interior, to remain here until the system 
needs it; when the tissues require glucose, this glycogen is 
re-transformed into glucose, and passes into the general 



45. What substances easily pass through animal membrane ? What are these substances 
called ? What substances pass through with great difficulty, if at all ? What are they 
called ? Why is this distinction not absolute ? What is dialysis ? Illustrate the process. 

46. Describe the process of the absorption of food, after it has reached the intestines in 
liquefied form. AVhat substances pass directly into the vessels and lacteals? How is glu- 
cose modified by the action of the liver ? What is this modified substance called ? 



DIGESTION 



141 



circulation. It will thus be seen that the liver plays a 
very important part in the process of 
nutrition, and acts as a storehouse of 
food. 

47. Circumstances Affecting Digestion. 

— What length of time is required for 
the digestion of food ? From observa- 
tions made, in the case of St. Martin, 
the Canadian already referred to, it has 
been ascertained that, at the end of two 
hours after a meal, the stomach is ordi- 
narily empty. How much time is needed 
to complete the digestion of food, within 
the small intestines, is not certain ; but 
from what we have learned respecting 
their methods of action, it must be evi- 

_ , i , •, n -it i ,, Fig. 31. — Two Intestinal 

dent that it largely depends upon the y ILLI . magnified ioo di- 
amount of starch and fat which the ameters 

„ , . . a.b, and c, Lacteals ; d, Blood- 

IOOd Contains. vessels 




9. Absorption of the Lacteals. — " The force by which the milky fluid 
moves upward through the lacteals is very considerable. This has been 
proved by the distension of the whole system of vessels, including the 
thoracic duct, even to the occurrence of rupture, when that duct has been 
tied in an animal a short time before it has been fed. The movement of 
the fluid thus, in some measure, resembles absorption by the spongioles 
at the extremities of the roots of trees, and the continuous rising of the 
sap. The thoracic duct may become diseased, and a serious derange- 
ment of nutrition take place. In the case of an unfortunate person, 
who was some years ago exhibited as a curiosity under the name of the 
'living skeleton,' was illustrated the slow starvation that may thus be 
produced. Although he was able to take food in abundant supply, he 
was not nourished by it. Finally he died, and an examination of his 
body disclosed the fact that the thoracic duct had been obstructed by 
disease, and absorption by the lacteals was prevented. Hard work 
directly after a hearty meal is bad practice. Remember the story of the 
two hounds. They were both fed alike in the morning ; one oi them 
was taken out to run on a hunt, the other was tied up at home. When 
the master came back from the hunt, both doss were killed, and their 



47. What length of time is required for the digestion of food 



142 DIGESTION 

48. In addition to the preparation which the food undergoes 
in cooking, which we have already considered, many circum- 
stances affect the duration of digestion ; such as the quality, 
quantity, and temperature of the food; the condition of the 
mind and body ; sleep, exercise, and habit. Eresh food, 
except new bread and the flesh of animals recently slain, is 
more rapidly digested than that which is stale ; and animal 
food more rapidly than that from the vegetable kingdom. 

49. Food should not be taken in too concentrated a form, 
the action of the stomach being favored when it is somewhat 
bulky ; but a large quantity in the stomach, especially if there 
is much liquid, often retards digestion. If the white of one 
egg be given to a dog, it will be digested in an hour, but if the 
white of eight eggs be given it will not disappear in four 
hours. A wine-glassful of ice-water causes the temperature 
of the stomach to fall thirty degrees ; and it requires a half- 
hour before it will recover its natural warmth — about a 
hundred degrees — at which the operations of digestion are 
best conducted. A variety of articles, if not too large in 
amount, is more easily disposed of than a meal made of a 
single article ; although a single indigestible article may inter- 
fere with the reduction of articles that are easily digested. 
{Bead Note 10.) 

stomachs examined. It was found that the hound that hunted still had 
the stomach full of food, while that of the stay-at-home was empty. 
When you have a hard piece of work on hand do not eat much ; the 
more you eat the weaker you are for the purpose." — Buckland (in part). 
10. Digestibility of Warm Food. — "It is very desirable that all 
cooked food should be taken hot. When it is eaten cold it reduces the 
temperature of the stomach, and both the nerves and vessels of the 
stomach are taxed in order to bring the temperature of the food thus 
taken up to that of the human body. Mankind in all ages seems to 
have discovered that it is desirable to prevent this tax upon the internal 
organs, and have taken their food hot in order to prevent it. It was 
death to the Roman slave to bring in his master's water tepid or cold — 
so much importance did they attach to hot water as drink. Many of 
our own beverages are taken hot even in summer weather ; and it is an 



48. Circumstances affecting duration of digestion ? Fresh food ? 

49. Food in concentrated form ? A large quantity of food ? Experiment on the dog 5 
Ice-water ? Variety of articles ? 



DIGESTION 143 

50. Strong emotion, whether of excitement or depression, 
checks digestion, as do also a bad temper, anxiety, business 
cares, and bodily fatigue. The majority of these conditions 
make the mouth dry — that is, they restrain the flow of the 
saliva ; and without doubt they render the stomach dry also, 
by preventing the flow of the gastric juice. And, as a general 
rule, we may decide, from a parched and coated tongue, that 
the condition of the stomach is not very dissimilar, and that it 
is unfit for the performance of digestive labor. This is one of 
the points which the physician bears in mind when he examines 
the tongue of his patient. {Bead Note 11.) 

51. The practice of eating at short intervals, or "between 
meals," as it is called, has its disadvantage, as well as rapid 
eating and overeating, since it robs the stomach of its needed 
period of entire rest, and thus overtasks its power. With the 
exception of infants and the sick, no persons require food more 
frequently than once in six hours. Severe exercise, either 
directly before or directly after eating, retards digestion; a 
period of repose is most favorable to the proper action of the 
stomach. The natural inclination to rest after a hearty meal 
may be indulged, but it should not be carried to the extent of 



economy of the vital powers to take hot meals rather than cold ones. As 
a rule, hot food is better than cold, in our climate, except in very hot 
weather ; in tropical climates only can food be taken with advantage 
when cold, or ice and iced drinks be used with impunity." — Lankester^s 
Manual of Health. 

11. On the Demands of Digestion. — " The system never does two 
things well at the same time. No one can meditate a poem and drive a 
saw simultaneously without dividing his force ; he may poetize fairly 
and saw poorly ; or he may saw fairly and poetize poorly ; or he may 
both saw and poetize indifferently. Brain-work and stomach-work inter- 
fere with each other if attempted together. The digestion of a dinner 
calls force to the stomach, and temporarily slows the brain : the experi- 
ment of trying to digest a hearty supper, and to sleep during the process, 
has sometimes cost the careless experimenter his life. The physiological 
principle is to do only one thing at a time, if you would do it well." — 
Dr. E. II. Clarke: Sex in Education. 



50. Strong emotion ? The tongue of the patient ? 

51. Eating between meals ¥ Severe exercise ? Sleep after meals t 



144 



DIGESTION 



sleeping ; since in that state the stomach, as well as the brain 
and the muscles, seeks release from labor. {Bead Notes 12 and 13.) 
52. The Kidneys. — Besides those already described, the 
abdominal cavity contains other important organs, viz., the 
kidneys and spleen. The kidneys are two in number, located in 

the loins behind the intestines, one 
on each side of the spinal column. 
They are shaped like a bean, being 
about four inches long, two inches 
wide, and one inch thick. The func- 
tion of the kidneys is to purify the 
blood by removing from it a poison- 
ous substance called urea and cer- 
tain waste products. If their action 
is in any way interfered with, blood- 
poisoning takes place, on account 
of the accumulation of urea, and 
effete materials in the system, pro- 
ducing coma, which rapidly proves 
fatal unless it is relieved. The 
watery fluid secreted by the kid- 
neys is carried by two tubes, called 
Bladder ureters, to the bladder. 




12. Work of Exertion. — "The best time to make great exertion is 
about two hours after a meal. It is not a good time before breakfast, 
although moderate work may be then performed ; and those who. go to 
work before breakfast should first take a cup of hot milk, tea, or coffee, 
or other simple food. The body is weakest before breakfast. 

"Violent or rapid exertion made by children, and also by stout and 
aged people, often injures, and sometimes causes disease of the heart, 
when the same taken in the ordinary way would do no harm. Rapidly 
running upstairs, or to meet a train, sometimes causes death. Hence, 
while exercise is of the utmost importance to health, it should be taken 
in a regulated and rational manner, and particularly by those who have 
passed the period of youth. But disease of the heart, even in youth, may 
often be traced to indiscretion in this particular, whether in rowing, run- 
ning, or jumping." — Edward Smith on Health. 

13. Tight Clothing interferes with Digestion. — " On one wet winter's 
day at Florence, some years ago, I had been spending the morning in the 



52. What are the kidneys and their functions ? 



DIGESTION 145 

53. The Spleen. — The spleen is situated on the left side of 
the abdomen behind the stomach. It is called the " milt " by 
the butcher. It has no duct, and its uses are not positively- 
known. In malarial fevers, it is sometimes much enlarged, 
and the individual is said to have an " ague cake." 

54. Effect of Alcohol upon Digestion. — The irritating effects 
of alcohol upon the lining of the stomach * are first seen in 
deranged digestive action, in loss of appetite, and at a later 
stage, in changes in the stomach's structure, principally by a 
thickening of the walls of that organ. (Bead Note 14.) 

studio of a sculptor of world-wide reputation. We had discussed the 
perfections of female beauty, and I felt that I was sitting at the feet of a 
thinker, as well as an ' elegans formarum spectator.' In the evening we 
met again at a hospitable palazzo, and, under cover of the waltz, from a 
quiet corner of observation, we saw hurling by in the flesh, much that we 
had been thinking of in the marble and the clay, and our eyes could not 
but follow one particular face, famous for the assistance its great natural 
beauty received from art. ' Face,' I said, but the mind of Hiram Powers 
was penetrating deeper, for he exclaimed, after a short silence : ' That 

is all very well, but I want to know where Lady puts her liver ! ' 

Where, indeed ! for, calculating the circumference of the waist by the 
eye, allowing a minimum thickness for the walls of the chest, an area for 
the spine, oesophagus, and great blood-vessels, the section of the waist 
seemed to admit of no room for anything else. In such a body the liver 
must be squeezed down into the abdomen, stick into its hollow neighbors, 
and infringe upon all the organs. The organ which suffers most is the 
unresisting stomach, which is dragged and pushed out of all form during 
the continuance of this packing process." — Dr. T. K. Chambers on the 
Indigestions. 

* Dyspepsia due to Alcohol. — "Many cases of dyspepsia are due to 
alcohol solely and wholly, and no reliance whatever can be placed upon 
the word, statement, or assertion under oath of a drunkard; for 'a 
drunkard is a liar.' And this holds good of both sexes, all ages, every- 
where and ever. 1 ' — Dr. J. M. Fothergill. 

14. Cordials, Bitters, etc. — "In health, alcohol no wise plays a 
friendly part in regard to digestion. And it is just here that a mistake 
is made by many persons who have been deluded into the use of what 
are termed 'cordials'; these are very strong alcoholic liquors, and they 
are supposed by those who use them to be especially appropriate at the 
end of a hearty meal. Absinthe, the pet poison of the Parisian, is one of 
these falsely-named ' cordial ' substances. These cordials are never less 



68. What is the location of the spleen ? 

54. How is tho digestion affected l>y alcohol ? 



146 DIGESTION 

Dr. Beaumont was able to observe the condition of the 
stomach of Alexis St. Martin (see paragraph 28, page 128) after 
alcoholic excesses. He states that the surface of the organ was 
overcharged with blood, at times drops of blood exuding from 
it ; and that its secretions became thick, unnatural, and slightly 
tinged with blood.* It is a fact beyond dispute that other 
organs concerned in the act of digestion, particularly the liver, 
become diseased by the habitual use of spirituous liquors. 
{Bead Note 15.) 

55. Effects of Alcohol on the Liver. — When alcohol is taken 
into the stomach it is absorbed, and is carried by the portal 
vein directly into the liver. The blood in the liver is thus 
made more stimulating, and repeated stimulation produces 
over-action, which results in impairment or loss of power to 
secrete healthy bile. For the same reason, organic changes 
take place more frequently in the liver, from the use of alcohol, 

welcome than after a substantial meal. So many misleading names have 
been given to beverages (Cordials, Bitters, etc.), that many persons have 
used them without knowing the evil consequences which follow. It is 
made clear by recent proofs that the so-called cordials are the most rapidly 
poisonous of all the spirituous beverages." 

* Alcohol and Digestion. — "The effects of alcohol upon digestion vary 
greatly according to the quantity imbibed; it may act as a temporary 
check, or in large doses it may completely arrest the digestive act : vomit- 
ing is frequently induced — the stomach thus. freeing itself from the hurt- 
ful intruder. The habitual use of spirits often gives rise to a most dis- 
tressing form of dyspepsia." 

15. Effect upon the Appetite. — " At a Peace Congress held at Frank- 
fort, Germany, the inn-keepers found it necessary to increase the price 
of board of the strangers attending the congress, the majority of whom 
were teetotalers, for the reason that their appetites required an amount 
of solid food in excess of that usually consumed by their own nationality, 
who are habitual drinkers of beer containing appreciable amounts of 
alcohol. 

"By direct contact, alcohol acts upon the stomach and leads to a 
destruction of its secreting tubules. Nothing with such certainty impairs 
the appetite and the digestive power as the continued use of strong alco- 
holic liquids. From the stomach it is absorbed, and with its distribution 
through the system it interferes with nutrition and leads to a diseased 
state of the liver, kidneys, and other organs." — Pavy. 



55. What effect produced on the liver by alcohol? 



DIGESTION 147 

than in any other organ. It first becomes enlarged, owing to 
congestion from obstruction of the circulation and excessive 
growth of the connective tissue. One result of this overgrowth 
is compression and diminution in size of the cells which secrete 
the bile. Another result is a hindrance to the flow of blood 
through the liver. The organ is not only diminished in size, 
but it becomes hardened and roughened — an appearance which 
has given it the name of hob-nailed liver or drunkard's liver. 
This condition not only interferes with the proper formation 
of bile, but it obstructs the return of blood from the organs in 
the abdomen, and we have dropsy as a consequence. 

56. The Effects of Alcohol on the Kidneys. — The action of 
alcohol on the kidneys is similar to that which takes place in 
the liver. The first effect of repeated stimulation by alcohol 
is an increase of the natural secretions of the organs, but this 
continued over-action, in obedience to a universal law, after- 
ward results in a diminished secretion and in injury to the 
substance of the kidney. " Granular degeneration," one of 
the forms of Bright's disease, takes place. The kidneys are 
unable to perform efficiently the duty of removing impurities 
from the blood ; urea, and other noxious materials accumulate, 
and the whole system is poisoned. 

57. The Effect of Tobacco on Digestion. — Very few persons 
are able to take up the habit of smoking without first experi- 
encing the sickening effect of tobacco upon the stomach. The 
use of tobacco has a perverting influence over the salivary 
glands, causing the secreted fluid to become so watery as to 
deprive it of its property of converting starch into sugar. In 
the case of some persons this amounts to a serious impairment 
of digestion, and can be relieved only by the abandonment of 
the offending substance. 

The habitual use of tobacco has a tendency to leave fctye 
mouth and throat in a condition of unnatural dryness, and this 
has the effect of an artificially produced thirst which has, in 



56. How are the kidneys affected by alcohol ? 

57. What effeot of tobacco ou digestion '! Upon the mouth? What are the '"twin 
vices" ? 



148 



DIGESTION 



many instances, led to the habit of taking alcoholic liquors. 
These two habits do not always co-exist in the same persons, 
but the danger that the one will lead up to the other is so 
great that they are frequently spoken of as the "twin vices." 

The young should appreciate this danger, and should also 
remember that the habit of using tobacco is most commonly 
established early in life, if at all ; very few persons, compara- 
tively, who have passed twenty years of age without forming 
the habit, adopt it in their later years. 



TOPICAL OUTLINE 



THE 

CAVITIES OF 
THE TRUNK 



Thorax or 
Chest 



Diaphragm 



Abdomen 



Shape 



Walls 



Sides ■ 



Front - 



f Conical, with the diaphragm 
1 as its base. 
! Back — Vertebral column. 
j Ribs. 

/ Intercostal muscles. 
I Sternum. 
1 Costal cartilages. 
Floor — Diaphragm. 
A muscular partition, dividing the thorax 
from the abdomen. Convex above and 
concave below. 

f Roof — Diaphragm. 
Back — Vertebral column. 
Sides and Front — Abdomi- 
nal muscles. 



Walls 



PROCESS 

OF 

DIGESTION 



Starchy foods \ 



f Solution commenced 
saliva. 



in the mouth by the 



Nitrogenous 
foods 



Absorption by 
Blood-vessels 



I Completed in the intestines by the intestinal 
I juices. 

r Solution commenced in the stomach by the 
gastric fluid. 
Continued in the intestines by the pancreatic 
fluid, and also (probably) by the intestinal 
l secretions. 
f Fat globules loosened from their nitrogenous 
cell-walls and membranes by the gastric 

Fats -j fluid. 

I Digested in the intestines by the bile and the 
I pancreatic fluid. 
I Mineral salts Dissolved by the various digestive fluids. 

From the mucous membrane in all parts of the alimentary 
canal. 

No power of selection — 

Every kind of food absorbed if dissolved, or if so finely 
divided that it can permeate the walls of the blood capil- 
laries. 



DIGESTION 



149 



LYMPHATIC 
SYSTEM 



Lacteals 



Other 
Lymphatics 

Glands . . . 



Thoracic duct 



The lymphatics of the intestines. 
Mauy originate in the villi of the small 
intestine. 

{During digestion — a milky fluid 
(chyle). 
During fasting — a watery fluid. 
I Absorb fatty substances. 
Absorb the fluid portion of blood (lympb) 
which has exuded through the blood- 
vessels. 
{ Also other substances for reorganization. 
j Engaged in elaborating blood from the 
i lymph and chyle. 
f In front of backbone, chiefly in thorax. 
| Receptaculum chyli — lower portion — situ- 
{ ated in the abdomen. 

j Receives lymph and chyle, and pours them 
I into the blood system. 



QUESTIONS FOR TOPICAL REVIEW 

PAGE 

1. What do you understand by nutrition ? 117 

2. How is the process of nutrition carried on ? 117 

3. What further can you state on the subject ? 118 

4. Describe the general plan of digestion 119 

5. How is the process of mastication carried on ? 119 

6. State what you can in relation to the formation of the teeth 120, 121 

7. What, in relation to their arrangement ? 120, 121 

8. What, in relation to the process of " shedding " ? 120 

9. In relation to the different forms of teeth in different animals? . . 122, 123 

10. What causes operate to injure or destroy the teeth ? 123 

11. What suggestions and directions are given for the preservation of 

the teeth ? 123, 124 

12. What do you understand by insalivation ? 124 

13. How is the process of insalivation carried on ? 124, 125 

14. Of what importance is the saliva to the process ? 125, 120 

15. Of what importance are mastication and insalivation ? l'_7 

10. Describe the consequences of rapid eating 127, 128 

17. What becomes of the food directly after it has undergone mastica- 

tion and insalivation ? 128 

18. Describe the location and formation of the stomach 128, 129 

19. Describe the process by which the gastric juice is formed 129, 130 

20. What are the properties and uses of the gastric juice ? 130 

21. What are the movements of the stomach, and what their uses? .... 131 

22. What further can you state on the subject ? 131 

23. What portions of the food are digested in the stomach ? 132, 133 

24. What are the first changes of digestion ? 132 

25. What further can you state in relation to the stomach ? 132, 133 

20. Describe the intestines 134 

27. Describe the process of intestinal digestion 134, 13,') 

28. What do you understand by absorption ? 136 



150 DIGESTION 



PAGE 

29. How is the process of absorption effected ? 137 

30. What are the lacteals, and of what use are they ? 138 

31. What length of time is required for the digestion of food ? 141 

32. What circumstances, of food, affect digestion ? 142 

33. What circumstances, of emotion, affect digestion ? 143 

34. What suggestions and directions are given upon the subject of eat- 

ing and drinking ? 142, 143 

35. Describe the kidneys and their office 144 

36. What happens when their action ceases ? 144 

37. Give the location of the spleen. Has it a duct ? 145 

38. How does alcohol affect digestion ? 145, 146 

39. Give the experiment on St. Martin 146 

40. State the effects of alcohol upon the liver 146, 147 

41. State the effects upon the kidneys 147 



CHAPTER VII 

THE CIRCULATION 

The Blood — Its Plasma and Corpuscles — Coagulation of the Blood — 
The Uses of the Blood — Transfusion — Change of Color — The Organs 
of the Circulation — The Heart, Arteries, and Veins — The Cavities 
and Valves of the Heart — Its Vital Energy — Passage of the Blood 
through the Heart — The frequency and Activity of its Movements — 
Tlie Pulse — The Spygmograph — The Capillary Blood-vessels — The 
Bate of the Circulation — Assimilation — Injuries to the Blood-vessels 
— Effects of Alcohol on Heart 

1. The Blood. — Every living organism of the higher sort, 
whether animal or vegetable, requires for the maintenance of 
life and activity, a circulatory fluid, by which nutriment is dis- 
tributed to all its parts. In plants, this fluid is the sap ; in 
insects, it is a watery and colorless blood; in reptiles and 
fishes, it is red but cold blood; while in the nobler animals 
and man, it is red and warm blood. 

2. The blood is the most important, as it is thje most abun- 
dant, fluid of the body ; and upon its presence, under certain 
definite conditions, life depends. On this account it is fre- 
quently, and very properly, termed "the vital fluid." The 
importance of the blood, as essential to life, was recognized in 
the earliest writings. In the narration of the death of the 
murdered Abel, it is written, "the voice of his blood crieth 
from the ground." In the Mosaic law, proclaimed over thirty 
centuries ago, the Israelites were forbidden to eat food that 
contained blood, for the reason that "the life of the flesh is in 
the blood." With the exception of a few tissues, such as the 
hair, the nails, and the cornea of the eye, blood everywhere 
pervades the body, as may be proved by puncturing any part 

1. What is required by every living organism ? In plants? insects? Reptiles? Man' 

2. Importance and abundance of blood ? Dependence of Hie? Abel? Mosaiolaw! 
In what part of the body is blood not found ? Quantity of blood in the bodj ! 

151 



152 



THE CIRCULATION 



with a needle. The total quantity of blood in the body is 
estimated at about one-eighth of its weight, or eighteen pounds. 

3. The color of the blood, in man and the higher animals, 
as is well known, is red; but it varies from a bright scarlet 
to a dark purple, according to the part whence it is taken. 
" Blood is thicker than water," as the adage truly states, and 
has a glutinous quality. It has a faint odor, resembling that 
peculiar to the animal from which it is taken. 

4. When examined under the microscope, the blood no 
longer appears a simple fluid, and its color is no longer red. 
It is then seen to be made up of two distinct parts : first, a 
clear, colorless fluid, called the plasma; and, secondly, of a mul- 
titude of minute solid bodies, or corpuscles, that float in the 
watery plasma. The plasma, or nutritive liquid, is composed 
of water richly charged with materials derived from the food, 
viz., albumen, which gives it smoothness; fibrin; certain fats; 
traces of sugar ; and various salts. 

5. The Blood Corpuscles. — In man, these remarkable "little 
bodies," as the meaning of the word corpuscles signifies, are of 

a yellow color, but by their vast 
numbers impart a red hue to the 
blood. They are very small, hav- 
ing a diameter of about -35V0 °^ an 
inch, and being one-fourth of that 
fraction in thickness; so that if 
3500 of them were placed in line, 
side by side, they would only ex- 
tend one inch; or, if piled one 
above another, it would take at 
least 14,000 of them to stand an 
inch high. Although so small in 
size they are very regular in form. As seen under the micro- 
scope, they are not globular or spherical, but flat, circular, and 
disc-like, with central depressions on each side, somewhat like 




— The Blood Corpuscles, 
higiily -magnified 



3. Color of blood ? Its consistence ? Odor ? 

4. What is stated of the blood as viewed under the microscope ? 

5. State what you can of the little bodies called corpuscles. 



THE CIRCULATION 153 

a pearl button that has not been perforated. In freshly-drawn 
blood they show a disposition to arrange themselves in little 
rolls like coins (Fig. 33). 

6. The size and shape of blood (red) corpuscles vary in dif- 
ferent animals. In man they are circular and flat, with a central 
depression on both sides, also in all warm-blooded quadrupeds, 
except the camel and lama, where they are oval. In birds, 
reptiles, and fish, they are oval, but with 

raised centre or nucleus. This variation is (£% ° 

often of vital importance in murder trials, ^ ^ 

where blood-stained weapons or clothing are a $ 

used as evidence. A microscopical examina- 
tion shows us the corpuscles, and we deter- 
mine from their shape, whether it was caused 
by blood from a warm-blooded quadruped, 
from a camel, or from a fowl or fish. But 
we cannot affirm that the stain was made by 
human blood, and not by that of the dog, ox, 
or sheep, because in all of these the corpuscles 
are shaped alike, and the size varies but little. 

7. The character of the blood of dead, ex- FlG - 34 - - «. Oval 

. Corpuscles of a fowl, b, 

tmct, and even fossil animals, such as the corpuscles of a frog, c, 
mastodon, has been ascertained by obtaining T1 ™seofa shark. 

' J ° The five small ones at 

and examining traces of it which had been the upper part of the 

, . , ., . -, , figure represent the hu- 

shut up, perhaps tor ages, in the circulatory man corpuscles magni- 
canals of bone. A means of detecting blood fied four hundred times, 
in minute quantities is found in the spectroscope, the same 
instrument by which the constitution of the heavenly bodies 
has been studied. If a solution containing not more than one 
one-thousandth part of a grain of the coloring matter of the 
corpuscle be examined, this instrument will detect it. 

8. The red corpuscles are of a soft and jelly-like consistency, 
without any distinctive cell membrane enclosing them. Some 
observers have claimed that this latter does exist, but it can- 
not be demonstrated. They are composed of an albuminous 
substance and a coloring matter, called haemoglobin, together 




<;. Size and shape of the red corpuscles? 7. How may blood in minute quantities !> 
detected? S. Describe the structure and constitution yA' the red corpuscles. 



154 THE CIRCULATION 

with mineral salts and water, the latter constituting more than 
half the bulk. The coloring matter, haemoglobin, has the 
power of readily absorbing oxygen, wherever that gas is found, 
and with equal facility parting with it wherever it is needed. 
Thus it is that the blood in its passage through the lungs 
absorbs the oxygen from the air, or as much of it as is needed. 
As the blood circulates throughout the tissues of the body, it 
supplies them with their needed oxygen. 

9. Besides these corpuscles, and floating along in the same 
plasma, are the white corpuscles. These are fewer in number, 
but larger, and globular in form. They are colorless, and their 
motion is less rapid than that of the other variety. The total 
number of both varieties of these little bodies in the blood is 
enormous. It is calculated that in a cubic inch of that fluid 
there are eighty -three millions, and at least five hundred times 
that number in the whole body. 

10. The white blood corpuscles exist in the blood, in the 
proportion of about one to three hundred of the red. They 
are nearly spherical in form, and are about one-half as large 
again in diameter as the red ones. They consist of a soft, 
somewhat viscid, finely granular substance, containing one or 
more ovoid nuclei. They are less yielding and slippery than 
the red, and adhere more readily to any surface with which 
they come in contact. If the blood in circulation in the web 
of the frog's foot be examined, it will be seen that the red 
globules form the centre of the current, whilst the white are 
often seen along the walls of the blood-vessel. They are capa- 
ble of independent movement, resembling in this the amoeba, 
already spoken of in the first chapter ; by means of this inde- 
pendent motion they are enabled to move from place to place, 
and even pass through the walls of the capillaries into the sur- 
rounding tissue. Nothing definite is known about their physi- 
ological functions. That they play an important part in the 
economy of the body cannot be doubted as judged from the 
fact that they are present in such considerable numbers. 
Some observers claim that they have an important part in the 

9. Size, shape, and color of white corpuscles ? 10. Proportion of white to red corpuscles ? 



THE CIRCULATION 155 

function of nutrition, being carriers of peptone and fat. 
Others claim that they act as destroyers of bacteria, acting 
in this way as general scavengers of the body. But neither 
these nor any other of the many theories advanced as to the 
functions of the white corpuscles is capable of positive demon- 
stration. {Read Note 1.) 

11. Coagulation. — The blood, in its natural condition in the 
body, remains perfectly fluid ; but within a few minutes after 
its removal from its proper vessels, a change takes place. It 
begins to coagulate, or assume a semi-solid consistence. If 
allowed to stand, after several hours it separates into two 
distinct parts, one of them being a dark red jelly, called 
the coagulum, or clot, which is heavy and sinks ; and the 
other, a clear, straw-colored liquid, called serum, which covers 
the clot. This change is dependent upon the presence in the 
blood of fibrin, which possesses the property of solidifying 
under certain circumstances, one of them being the separation 
of the blood from living tissues. The color of the clot is due to 
the entanglement of the corpuscles with the fibrin. 

12. In this law of the coagulation of the blood is our safe- 
guard against death by hemorrhage, or undue loss of blood. If 



I. The Blood. — " You feel quite sure that blood is red, do you not ? 
Well, it is no more red than the water of a stream would be if you were 
to fill it with little red fishes. Suppose the fishes to be very, very small — 
as small as a grain of sand — and closely crowded together through the 
whole depth of the stream, the water would look red, would it not ? 
And this is the way in which the blood looks red : only observe one 
thing — a grain of sand is a mountain in comparison with the little red 
bodies that float in the blood, which we have likened to little fishes. If 
I were to tell you they measured about the 3200th part of an inch in 
diameter, you would not be much the wiser ; but if I tell you that in a 
single drop of blood, such as might hang on the point of a needle, there 
are a million of these bodies, you will perceive that they are both very 
minute and very numerous. Not that any one has ever counted them, 
as you may suppose, but this is as close an estimate as can be made in 
view of what is known of their minute size. 11 — Mac&s History of a 
Mouthful of Bread. 

II. The blood in its natural condition in the body ? Describe the process by which the 
coagulation of Mood takes place. 

12. If coagulation were Impossible ? llow is it in fact ? 



156 THE CIRCULATION 

coagulation were impossible, the slightest injury in drawing 
blood would prove fatal. Whereas now, in many cases, bleed- 
ing ceases spontaneously, because the blood, as it coagulates, 
stops the mouths of the injured blood-vessels. In another class 
of cases, where larger vessels are cut or torn, it is ordinarily 
sufficient to close them by a temporary pressure ; for in a few 
minutes the clot will form and seal them up. In still more 
serious cases, where the blood-vessel is of large size, the sur- 
geon is obliged to tie a ligature about it, thus preventing the 
force of the blood-current from washing away the clots, which, 
forming within and around the vessel, close it effectually. 

13. It is worthy of remark that this peculiarity is early 
implanted in the blood, even before birth, and in advance of 
any existing necessity for it — thus anticipating and guarding 
against danger. But this is not all. Of most of the inferior 
animals, which, as compared with man, are quite helpless, the 
blood coagulates more rapidly, and in the case of the birds, 
almost instantly. The relative composition of fluid and coagu- 
lated blood may be thus represented : 

Fluid Blood Coagulated, Blood 

Plasma^— Serum : — Serum 

^^^-^Fibrin^^ 

Corpuscles Corpuscles— ^^Clot 

{Bead Xote 2.) 

14. The Uses of the Blood. — The blood is the great pro- 
vider and purifier of the body. It both carries new materials 
to all the tissues, and removes the worn-out particles of matter. 

2. Experiment. Coagulation of Blood. — The coagulation of blood 
can be shown to a class with but little trouble. Obtain from a butcher or 
slaughter-house about a pint of fresh blood, have it drawn into a tin can 
or pail, and put it immediately into a freezing mixture of ice and salt. If 
it be during the winter and freezing, this is not necessary, as freezing 
suspends coagulation. 

13. What is worthy of remark ? Coagulation of the blood of inferior animals ? Of the 
blood of birds ? 

14. The blood, as a provider and purifier ? What uses does the blood subserve ? Ex- 
periments ? Transfusion ? 



THE CIRCULATION 157 

This is effected by the plasma. It both conveys oxygen and 
removes carbonic acid. This is done through the corpuscles. 
Some singular experiments have been tried to illustrate the 
life-giving power of the blood. An animal that has bled so 
freely as to be at the point of death, is promptly brought back 
to life by an operation called transfusion, by which' fresh blood 
from a living animal is injected into the blood-vessels of his 
body. {Bead Note 3.) 

15. It is related that a dog, deaf and feeble from age, had 
hearing and activity restored to him by the introduction into 
his veins of blood taken from a young dog; and, that a horse, 
twenty-six years old, having received the blood of four lambs, 
acquired new vigor. And further, that a dog, just dead from 
an acute disease, was so far revived by transfusion, as to be 
able to stand and make a few movements. 

16. Transfusion has been practised upon man. At one time, 
shortly after Harvey's discovery of the "Circulation of the 
Blood," it became quite a fashionable remedy, it being thought 

Fill a glass vessel with the blood, and observe the different steps in its 
coagulation. In about two to three minutes it becomes viscid, and after 
about five to ten minutes it has assumed a jelly-like character, so that the 
vessel can be turned over without spilling its contents. Now will be seen 
on the surface of the jelly a few drops of fluid, which rapidly multiply, 
so that soon a layer of straw-colored fluid is floating on the surface. This 
fluid increases, and the clot contracts more and more, until at the end of 
about twelve hours, the process is complete, and we have a firmly con- 
tracted clot floating in a clear straw-colored fluid. The clot is composed 
of the fibrin and corpuscles, and the fluid is the serum, colored by a few 
red corpuscles. 

3. The Work of the Blood. — " The blood, which is our life, is a 
complex fluid. It contains the materials out of which the tissues are 
made, and also the debris which results from the destruction of the same 
tissues, — the worn-out cells of brain and muscle, — the cast-off clothes 
of emotion, thought, and power. It is the common carrier, conveying 
unceasingly to every gland and organ, the fibrin and albumen which 
repair their constant waste, thus supplying their daily bread. Like the 
water flowing through the canals of Venice, that carries health and wealth 
to the portals of every house, and filth and disease from every doorway, 



15. The case of the rienf nnil feeble dog ? Horse ? Demi dog ? 

16, Transfusion, as a fashionable remedy ? What further of transfusion : 



158 THE CIRCULATION 

possible by it to cure all forms of disease, and even to make 
the old young again. But these claims were soon found to be 
extravagant, and many unhappy accidents occurred in its prac- 
tice; so that being forbidden by government and interdicted 
by the Pope, it rapidly fell into disuse. At the present time, 
however, it is sometimes resorted to in extreme cases, when 
there has been a great and rapid loss of blood ; and there are 
upon record several instances where, other means having 
failed, life has been restored or prolonged by the operation of 
transfusion. 

17. This reviving power of the blood seems to reside in the 
corpuscles ; for transfusion, when performed with the serum 
alone, has, in every case, proved fruitless. Now, though so 
much depends upon the blood and its corpuscles, it is a mis- 
take to suppose that in them alone is the seat of life, or that 
they are, in an exclusive manner, alive. All the organs and 
parts of the body are mutually dependent one upon the other, 
and the complete usefulness of any part results from the har- 
monious action of the whole. 

18. Change of Color. — The blood undergoes a variety of 
changes in its journey through the system. As it visits the 
different organs it both gives out and takes up materials. In 
one place it is enriched, in another it is impoverished. By 
reason of these alterations in its composition, the blood also 
changes its color. In one part of the body it is bright red, or 
arterial ; in another it is dark blue, or venous. In the former 
case it is pure, and fit for the support of the tissues ; in the 
latter, it is impure and charged with effete materials. (The 
details of the change from dark to bright will be given in the 
chapter on Bespiration.) {Read Notes 4, 5, and 6.) 

the blood flowing through the canals of our organization carries nutriment 
to all tissues, and refuse from them." — Clarke's Sex in Education. 

4. On Purifying the Blood. — "By some the blood is regarded as the 
source of all diseases, and to ' purify the blood ' is the object of their 
treatment. Quacks seize on this notion, and in sublime ignorance of the 



17. The seat of the reviving power of the blood ? What further is related ? 
IS. Changes in the blood ? What further is stated '? 



THE CIRCULATION 159 

19. Circulation. — The blood is in constant motion during 
life. From the heart, as a centre, a current is always setting 
toward the different organs ; and from these organs a current 
is constantly returning to the heart. In this way a ceaseless 
circular movement is kept up, which is called the Circulation 
of the Blood. This stream of the vital fluid is confined to 
certain fixed channels — the blood-vessels. Those branching 
from the heart are the arteries ; those converging to it are the 
veins. The true course of the blood was unknown before the 
beginning of the seventeenth century. In 1619 it was dis- 
covered by the illustrious William Harvey. Like many other 
great discoverers, he suffered persecution and loss, but unlike 
some of them, he was so fortunate as to conquer and survive 
opposition. He lived long enough to see his discovery uni- 
versally accepted, and himself honored as a benefactor of 
mankind. 

nature of the blood they profess to purify, and of the means by which 
their drugs could possibly purify it, make fortunes out of the credulity of 
the public. I would warn you against this notion of '• purifying ' the 
blood. The blood is not like a river into which anything can be intro- 
duced from without. It gets rid of, or destroys, all substances which 
intrude — all which do not form part and parcel of its own structure ; or, 
failing in that, it ceases to act as living blood." — George Henry Lewes. 

5. By Means of the Blood, Exercise Benefits the Whole Body. — 
"The employment of the muscles in exercise not only benefits their 
especial structure, but it acts on the whole system. When the muscles 
are put in action, the capillary blood-vessels with which they are supplied 
become more rapidly charged with blood, and active changes take place, 
not only in the muscles, but in all the surrounding tissues. The heart is 
thus required to supply more blood, and accordingly beats more rapidly 
in order to supply the demand. A large quantity of blood is sent through 
the lungs, and larger supplies of oxygen are taken in and carried to the 
various tissues of the body." The oxygen engenders a large amount of 
heat, which produces an action on the skin whereby the increase of heat 
may be got rid of. By this means the skin is exercised, the perspiration 
is poured forth, the surface is caused to glow and is kept in health. 
" Not only are these organs benefited by the increased circulation of the 
blood, produced by exercise, but wherever the blood is sent, changes of a 
healthful character occur. The brain and the rest of the nervous system 
are invigorated ; the stomach has its powers of digestion improved ; and 



li). Motion of the blood ? What is meant by the olroulation of the blood S How con- 
fined } Dlsoovery made by Harvey '.' 



160 THE CIRCULATION 

20. The Heart. — The heart is the central engine of the cir- 
culation. In this wonderful little organ, hardly larger than 
a man's fist, resides that sleepless force by which, during the 
whole of life, the current of the blood is kept in motion. It 
is placed in the middle and front part of the chest, inclining 
to the left side. The heart-beat may be felt and heard between 
the fifth and sixth ribs, near the breast-bone. The shape of 
the heart is conical, with the apex or point downward and in 

the liver, pancreas, and other organs perform their functions with more 
vigor." — Lankestefs Manual of Health. 

6. Experiment. The Heart. — To demonstrate the physiological 
anatomy of the heart will require some dissecting, and a little more care 
and work than the other experiments, but the teacher will be fully 
rewarded by the close attention and great interest shown by the pupils. 

Obtain from your butcher a bullock's heart inclosed in the pericardium 
or "bag." Instruct him to cut it out carefully and as high up as he can, 
so as not to injure it, and so as to leave of the large blood-vessels as much 
attached as is possible. 

Cut away all the fat surrounding the heart and great blood-vessels ; 
cut open the pericardium from apex to base, and partly away from the 
latter, so as to give room for exposing the cavities of the heart. The 
latter should be opened by two incisions along the septum separating the 
right from the left heart. The incision should run from apex to base, 
laying open both ventricle and auricle. Cut open all the large vessels 
found at the base, into the cavities to which they lead. 

Going from without inward observe and explain the different parts as 
follows : 

1. The Pericardium. — Note its structure and smooth, shining inner 
surface. Show how it surrounds the heart, and how it is attached along 
the base and great blood-vessels. 

2. General Structure of the Heart. — Show the thin-walled auri- 
cles ; the difference between the thickness oi the walls of the ventricles ; 
the difference in structure between the arteries and veins; demonstrate 
the two coronary arteries and their accompanying veins. 

3. Right Auricle and Ventricle. — Demonstrate the venae cavse and 
their entrance into the auricle ; the auriculo-ventricular valves between 
the two cavities ; the structure, attachment, and action of the valves ; the 
pulmonary artery. 

4. Left Auricle and Ventricle. — Demonstrate the pulmonary veins 
and their entrance into the auricle ; the mitral valve between auricle and 
ventricle ; the aortic valve, its structure, action, and attachment ; the 
structure and great strength of the aorta. 



20. Office of the heart ? Location of the heart ? Its beat ? Its shape ? Protection to 
the heart ? What else is said in relation to the heart ? 



THE CIRCULATION 161 

front. The base, which is upward, is attached so as to hold it 
securely in its place, while the apex is freely movable. In 
order that loss of power from friction may be obviated, the 
heart is enclosed between two layers of serous membrane, 
which forms a kind of sac. This membrane, called the peri- 
cardium, is as smooth as satin, and itself secretes a fluid in 
sufficient quantities to keep it at all times well lubricated. 
The lining membrane of the heart, called the endocardium, is 
extremely delicate and smooth. {Bead Note 7.) 

21. The Cavities of the Heart. — The heart is hollow, and so 
partitioned as to contain four chambers or cavities ; two at the 
base, known as the auricles, from a fancied resemblance to the 
ear of a dog, and two at the apex or point, called ventricles. 
An auricle and a ventricle on the same side communicate with 
each other, but there is no opening from side to side. It is 
customary to regard the heart as a double organ, and to speak 
of its division into the right and left heart. For while both 
halves act together in point of time, each half sustains an 
entirely distinct portion of the labor of the circulation. The 
right side always carries the dark or venous blood, and the 
left always circulates the bright or arterial blood. 

22. If we examine the heart, we at once notice that, though 
its various chambers have aboat the same capacity, the walls 
of the ventricles are thicker and stronger than those of the 
auricles. This is a wise provision, for it is by the powerful 
action of the ventricles that the blood is forced to the most 
remote regions of the body. The auricles, on the contrary, 
need much less power, for they simply discharge their contents 
into the ventricles below. (Figs. 35 and 36.) (See Note (>.) 

The two ventricles, moreover, are upon different levels. 
The right ventricle is somewhat in front of and above the 
left, so that, in viewing the heart from the front, we would 
look at the right ventricle, and in viewing the heart from be- 
hind, at the left; the left ventricle, being longer ami narrower 
than the right, and projecting below the right, forms the apex 

21. Formation of the heart ? Right and left heart ? 

22. Capacity of the ohambers of the heart ? The auricles ? 



162 



THE CIRCULATION 



of the heart. The difference in the thickness of the walls of 
the two ventricles is accounted for by the fact that the right, 
having thinner walls than the left, has only to pump the blood 
through the lungs, whereas the left ventricle has to pump the 
entire volume of blood through the whole body. The valves 
separating the different chambers of the heart are named as fol- 
lows : that between the right auricle and right ventricle is called 
the tricuspid; that separating the left auricle from the left 
ventricle, the mitral. There are also two sets of valves guard- 
ing the exit from the ventricles, called the semi-lunar valves. 

23. Action of the Heart. — The substance of the heart is of a 
deep red color, and its fibres resemble those of the voluntary 
muscles by which we move our limbs. But the heart's move- 
ments are entirely involuntary. The advantage of this is 
evident ; for if it depended 
upon us to will each move- 
ment, our entire attention 
would be thus engaged, 
and we would find no time 
for study, pleasure, or even 
sleep. The action of the 
heart consists in alternate 
contractions and expan- 
sions. During contraction 
the walls come forcibly to- 
gether, and thus drive out 
the blood. They then ex- 
pand and receive a renewed 
supply. These movements 
are called respectively sys- 
tole and diastole. The latter 
may be called the heart's 
period of repose; and al- 
though it lasts only during 
two-fifths of a heart-beat, or about a third of a second, yet 
during the day it amounts to more than nine hours of total rest. 




Fig. 37.— Section of the Heart 

A, Eight Ventricle E, F, Inlets to the Ventricles 

B, Left Ventricle G, Pulmonary Artery 

C, Right Auricle H, Aorta 

D, Left Auricle 



'23. Substance of the heart ? Its fibres ? Its movements ' 
movements ? Action of the heart? Its period of rest ? 



The advantage of such 



THE CIRCULATION 



163 



24. A remarkable property of the tissue of the heart is its 
intense vitality. For while it is more constantly active than 
any other organ of the body, it is the last to part with its vital 
energy. This is especially interesting in view of the fact that 
after life is apparently extinguished, as from drowning, or 
poisoning by chloroform, there yet lingers a spark of vitality 
in the heart, which, by continued effort, may be fanned into a 
flame so as to revivify the whole body. In cold-blooded ani- 
mals, this irritability of the heart is especially remarkable. 




Fig. 38. — Diagram showing the Position Fig. 39. — Diagram showing the Position 
of the Valves of the Heart while of the Valves of the Heart during 
the Walls are relaxed the Contraction of the Ventricles 

The heart of a turtle will pulsate, and the blood circulate for a 
week after its head has been cut off ; and its heart will throb 
regularly many hours after being cut out. The heart of a frog 
or serpent, separated entirely from the body, will contract at 
the end of ten or twelve hours; that of an alligator has been 
known to beat twenty-eight hours after the death of the 
animal. 

25. Passage of the Blood through the Heart. — Lot us now 
trace the course of the blood through the several cavities of 



24. Kemarkablo property of the tissue of the heart ? How shown ? How interesting ? 
In cold-blooded animals t Heart of a turtle ? Of a frog f Alligator ? 

25, Course of the blood through the heart J Course of heart-currents ? 



164 THE CIRCULATION 

the heart. In the first place, the venous blood, rendered dark 
and impure by contact with the changing tissues of the body, 
returns to the right heart by the veins. It enters and fills the 
right auricle during its expansion ; the auricle then contracts 
and fills the right ventricle. Almost instantly, the ventricle- 
contracts forcibly and hurries the blood along the great artery 
of the lungs, to be purified in those organs. Secondly, having 
completed the circuit of the lungs, the pure and bright arterial 
blood enters the left auricle. This now contracts and fills the 
left ventricle, which cavity, in its turn, contracts and sends the 
blood forth on its journey again through the system. This 
general direction from right to left is the uniform and undevi- 
ating course of heart-currents. 

26. The mechanism which compels this regularity is as sim- 
ple as it is beautiful. Each ventricle has two openings, an 
inlet and an outlet, each of which is guarded by strong cur- 
tains, or valves. These valves open freely to admit the blood 
entering from the right, but close inflexibly against its return. 
Thus, when the auricle contracts, the inlet valve opens ; but as 
soon as the ventricle begins to contract, it closes promptly. 
The contents are then, so to speak, cornered, and have but one 
avenue of escape — that through the outlet valve into the 
arteries beyond. As soon as the ventricle begins to expand 
again, this valve shuts tightly and obstructs the passage. The 
closing of these valves occasions the two heart-sounds, which 
Ave hear at the front of the chest. (Figs. 38, 39. 40. and 41.) 

27. Frequency of the Heart's Action. — The alternation of 
contraction and expansion constitutes the heart-beats. These 
follow each other not only with great regularity, but with 
great rapidity. The average number in an adult man is about 
seventy-two in a minute. But the heart is a susceptible 
organ, and many circumstances affect its rate of action. Heat, 
exercise, and food increase its action; cold, fasting, and sleep 
diminish it. Posture, too, has a curious influence ; for if while 



26. Openings of the ventricles ? How guarded ? Hoav do the valves operate ? The 
consequence ? Heart-sounds ? 

27. Heart-beats ? The heart as a susceptible organ ? Heat, exercise, etc. ? Posture ? 



THE CIRCULATION 165 

sitting the beats of the heart number seventy-one, standing 
erect will increase them to eighty-one, and lying down will 
lower them to sixty-six. {Bead Note 8.) 

28. The modifying influence of mental emotions is very 
powerful. Sudden excitement of feeling will cause the heart to 
palpitate, or throb violently. Depressing emotions sometimes 
temporarily interrupt its movements, and the person faints in 
consequence. Extremes of joy, grief, or fear have occasionally 
suspended the heart's action entirely, and thus caused death. 
The rate of the heart-beat may. be naturally above or below 
seventy -two. Thus it is stated that the pulse of the savage is 
always slower than that of the civilized man. Bonaparte and 
Wellington were very much alike in their heart pulsations, 
which were less than fifty in the case of each. {Bead Note 9.) 

7. The Heart is Injured by Over-exertion. — "During exertion, if the 
heart is not oppressed, its movements, though rapid and forcible, are reg- 
ular and equal. But when it becomes embarrassed, the pulse-beats are 
quick, unequal, and at last become irregular, indicating injury to the 
organ. All great and sudden efforts are to be carefully avoided ; exces- 
sive exercise often produces palpitation, and sometimes enlargement and 
valvular disease of the heart." — Huxley. 

"No great intellectual thing was ever done by great effort; a great 
thing can only be done by a great man, and he does it without effort. 
The body's work and the head's work are to be done quietly, and com- 
paratively without effort. Neither limbs or brain are ever to be strained 
to their utmost ; that is not the way in which the greatest quantity of 
work is to be got out of them ; they are never to be worked furiously, but 
with tranquillity and constancy. We are to follow the plough from sunrise 
to sunset, but not to pull in race-boats at the twilight ; we shall get no 
fruit of that kind of work — only disease of the heart." — Buskin. 

8. Fainting. — "When the heart suddenly ceases to act, fainting or 
swooning is very apt to take place. This takes place for the reason that 
the brain feels most speedily the lack of its supply of blood. Many cir- 
cumstances may cause a faint — such as a fright, joy, excitement, the 
sight of blood, or the breathing of foul air ; or it may be due to disease 
of the heart. In some persons, fainting becomes a kind of habit ; they 
fall into a fainting fit on very slight agitation. In them the appearances 
are much worse than the reality, especially to those who are not familiar 
with the ailment. Hut persons who faint after exhaustion, fatigue, fast- 
ing, or anguish, require prompt attention. The ordinary signs are great 



28. Mental emotions? Sadden exoitementi Excessive joy? The heart-beat mw:- 

Bouapurte aud Wellington ? 



166 THE CIRCULATION 

29. Activity of the Heart. — The average number of heart- 
beats during a lifetime may be considered as at the rate of 
seventy-two per minute, although this estimate is somewhat 
low, for during several years of early life the rate is above one 
hundred a minute. In one hour, then, the heart pulsates four 
thousand times ; in a day, one hundred thousand times ; and 
in a year, nearly thirty-eight million times. If we compute 
the number during a lifetime — forty years being the present 
average longevity of civilized mankind — we obtain as the vast 
aggregate, fifteen hundred millions of pulsations. {Read Note 10.) 

pallor, loss of sensation, and trembling of the limbs and loss of power 
over the muscles ; the breathing and pulse go on imperfectly or stop. 
The first thing to do is to place the head low, thus favoring the supply of 
blood to the brain ; the very act of falling is often sufficient to restore 
consciousness. Water may be sprinkled on the face, hartshorn held to 
the nose, or mustard over the heart. Pure air is a great restorative ; 
allow a current of fresh air to flow over the face, and loosen any tight 
bands that may confine the chest.'" — Dr. J. Knight (in part). 

9. The Heart a Vital Machine. — •' The heart is a machine. It is an 
organ constructed of muscular chambers and communicating passages, 
and supplied with mechanical contrivances, adapted to guide the stream 
of blood passing through it, and to prevent a reflux in the backward 
direction. Does not this take away wonderfully from the character of 
fanciful mystery with which poets and sentimentalists have invested it ? 
The heart that we have always heard of as the centre of the affections, 
the home of sensibility, the dwelling-place of courage, of faith, of hope, 
and all the rest of the virtues, is after all, nothing but an organ to serve 
for the impulsion of the blood — a mere force-pump, a machine. Does 
not this bring down our ideas, and show that no poetical mystery can 
escape the searching investigation of the anatomist ? Not at all. 

" For this machine that we carry about with us in our breasts is alive. 
There, at its post, at the central point of the circulation, with the soft 
lobes of the lungs folded round it like a curtain, it contracts and relaxes, 
and relaxes and contracts, with a steady and unremitting industry that 
by itself is something worthy of our admiration. No other muscle in the 
body can do this. By some incomprehensible vitality of its own, it keeps 
up its rhythmical contractions without the aid of our will and even with- 
out our knowledge. While you are asleep and while you are awake, from 
the first moment of your birth, even from before your birth, up to the 
present time, it has never for one moment stopped or flagged in its move- 
ments, for if it were to do so death would be the result. 1 ' — Dr. J. C. 
Dalton. 



Average number of neart-beats ? In one hour ? Year ? Lifetime ? 



-3 

W 

ft 

q 

o 
2; 

o 





THE CIRCULATION 167 

30. Again, if we estimate the amount of blood expelled by 
each contraction of the ventricles at four ounces, then the 
weight of the blood moved during one minute will amount to 
eighteen pounds. In a day it will be about twelve tons ; in a 
year, four thousand tons ; and in the course of a lifetime over 
one hundred and fifty thousand tons. These large figures 
indicate, in some measure, the immense labor necessary to 
carry on the interior and vital operations of our bodies. In 
this connection, we call to mind the fanciful theories of the 
ancients in reference to the uses of the heart. They regarded 
it as the abode of the soul and the source of the nobler emo- 
tions — bravery, generosity, mercy, and love. The words cour- 
age and cordiality are derived from a Latin word signifying 
heart. Many other words and phrases, as hearty, heart-felt, to 
learn by heart, and large-hearted, show how tenaciously these 
exploded opinions have fastened themselves upon our language. 

31. At the present time, the tendency is to ascribe purely 
mechanical functions to the heart. This view, like the older 
one, is inadequate ; for it expresses only a small part of our 
knowledge of this organ. The heart + is unlike a simple ma- 
chine, because its motive power is not applied from without, 
but resides in its own substance. Moreover, it repairs its own 
waste, it lubricates its own action, and it modifies its move- 
ments according to the varying needs of the system. It is 
more than a mere force-pump, just as the stomach is something 
more than a crucible, and the eye something more than an 
optical instrument. {Head Note 11.) 

32. The Arteries. — The tube-like canals which carry the 
blood away from the heart are the arteries. Their walls are 



10. The Heart. — " You all know where it is. It is the most wonder- 
ful little pump in the world. There is no steam-engine half so clever at 
its work, or so strong. There it is, in every one of us, beat, beating — all 
day and all night, year after year, never stopping, like a watch ticking ; 
only it never needs to be wound up, — God winds it up once for all." — 
Author of " Bab and His Friends." 



80. Amount of blood expelled ? Theories ot* the ancients ? 

81. The tendency at. the present time ? Why is this view inadequate ? 
32. What are the arteries ? Their walls ? Their membrane \ 



168 THE CIRCULATION 

made of tough, fibrous materials, so that they sustain the mighty 
impulse of the heart, and are not ruptured. In common with 
the heart, the arteries have a delicately smooth lining mem- 
brane. They are also elastic, and thus re-enforce the action 
of the heart; they always remain open when cut across, and 
after death are usually found empty. 

33. The early anatomists observed this condition, and sup- 
posing that it existed during life, came to the conclusion that 
these tubes were designed to act as air-vessels — hence the 
name artery, from Greek words which signify "containing air." 
This circumstance affords us an illustration of the mistaken 
notions of the ancients in reference to the internal operations 
of the body. Cicero speaks of the arteries as " conveying the 
breath to all parts of the body." 

34. The arterial system springs from the heart by a single 
trunk, like a minute and hollow tree, with numberless branches. 
As these branches leave the heart, they divide and subdivide, 
continually growing smaller and smaller, until they can no 
longer be traced by the naked eye. If, then, we continue the 
examination by the aid of a microscope, we see these small 
branches sending off still smaller ones, until all the organs of 
the body are penetrated by arteries. 

35. Histology of the Arteries. — The arteries have three prin- 
cipal coats. An inner, or epithelial coat; a middle coat con- 
taining elastic fibrous tissue, and unstriped muscular fibres 
arranged transversely around the vessel ; and an external coat 
of condensed connective tissue. The principal difference be- 
tween the larger and smaller arteries is in the structure of 
their middle coat. In the smaller arteries this is composed 
exclusively of muscular fibres. In arteries of medium size it 
contains both muscular and elastic tissue, whilst in those of 
the largest calibre it consists of elastic tissue only ; therefore, 
the large arteries possess much elasticity and but little con- 
tractility, while in the smaller these conditions are reversed. 

33. Early anatomists ? The service of the illustration ? 

34. The arterial system ?. The branches aud sub-branches of the arteries ? 

35. What are the three principal coats of the arteries ? The principal difference between 
the larger and smaller arteries ? 



THE CIRCULATION 169 

36. The Pulse. — With each contraction of the left side of 
the heart, the impulse causes a wave-like motion to traverse 
the entire arterial system. If the arteries were exposed to 
view, we might see successive waves speeding from the heart 
to the smallest of the branches. The general course of the ar- 
teries is as far as possible from the surface. This arrangement 
is certainly wise, as it renders them less liable to injury — the 
wounding of an artery being especially dangerous. It also 
protects the arteries from external and unequal pressure, by 
which the force of the heart would be counteracted and wasted. 
Accordingly, we generally find these vessels close to the bones, 
or hiding behind the muscles and within the cavities of the 
body. 

37. In a few situations, however, the arteries lie near the 
surface; and if we apply the finger to any of these parts, 
we shall distinctly feel a throbbing motion taking place in 
harmony with the heart-beat. This is part of the wave-motion 
just mentioned, and is known as the pulse. All are familiar 
with the pulse at the wrist, in the radial artery ; but it is not 
peculiar to that position, for it may be felt in the carotid of 
the neck, in the temporal at the temple, and elsewhere, espe- 
cially near the joints. 

38. Since the heart-beat makes the pulse, whatever affects 
the former affects the latter also. Accordingly, the pulse is 




Fig. 42. — The Form of the Pulse 



a good index of the state of the health, so far as the health 
depends upon the action of the heart. It informs the physi- 



11. The Beating of the Pulse. — " According to experiments made in 
Paris, the pulse of a lion beats forty times a minute ; that of a tiger, 



86. Successive undulations from the heart? Course of the arteries ? Protection of th< 
arteries? General location of the arteries ? 

37. Where do the arteries He ? it' we apply the finger ? Pulse ? Where felt ! 



170 THE CIRCULATION 

cian of the condition of the circulation in four particulars 
— its rate, regularity, force, and fulness ; and nearly every 
disease modifies in some respect the condition of the pulse. 
A very ingenious instrument, known as the sphygmograph, or 
pulse-writer, has recently been invented, by the aid of which 
the pulse is made to write upon paper its own signature, or 
rather to sketch its own profile. This instrument shows with 
great accuracy the difference between the pulses of health and 
those of disease. In Fig. 42 is traced the form of the pulse in 
health, which should be read from left to right. That part of 
the trace which is nearly perpendicular coincides with the 
contraction of the ventricles, while the wavy portion marks 
their dilatation. {Bead Note 12.) 

39. The Veins. — The vessels by which the blood returns to 
the heart are called veins. They, like the arteries, contain 
three coats, — inner, middle, and exterior. They are largely, 
however, composed of condensed connective tissue, and contain 
a much smaller quantity of muscular and elastic fibres. They 
are consequently more flaccid and compressible than the 
arteries, and are less elastic and contractile. At first they 
are extremely small; but uniting together as they advance, 
they constantly increase in size, reminding us of the way in 
which the fine rootlets of the plant join together to form the 
large roots, or of the rills and rivulets that flow together to 
form the large streams and rivers. In structure, the veins 
resemble the arteries, but their walls are comparatively in- 
elastic. They are more numerous and communicate with 
each other freely in their course by means of interlacing 
branches. 



ninety-six times ; of a tapir, forty-four times ; of a horse, forty times ; of 
a wolf, forty-five times ; of a fox, forty-three times ; of a bear, thirty- 
eight times ; of a monkey, forty-eight times ; of an eagle, one hundred 
and sixty times. It was impossible to determine the beatings of the 
elephant's pulse. A butterfly, however, it was discovered, experienced 
sixty heart pulsations in a minute." 



3S. The pulse as an index ? Of what does it inform the physician ? Instrument for 
recording pulsation ? 

39. What are the veins ? How do thev form ? What do thev resemble ? 



THE CIRCULATION 



111 



40. But the chief point of distinction is in the presence of 
the valves in the veins. These are little folds of membrane, 
disposed in such a way that they open only to receive the 
blood flowing toward the heart, and close against a current in 
the opposite direction. Their position in the veins on the back 
of the hand may be readily observed, if we first obstruct the 
return of blood by a cord tied around the forearm or wrist. 





Fig. 43. — Vein with Valves 

OPEN 



Fig. 44. — Vein with Valves closed ; 
the Stream of Blood passini; off 
by a Lateral Branch 



In a few moments the veins will appear swollen, and upon 
them will be seen certain prominences, about an inch apart. 
These latter indicate the location of the valves, or, rather, they 
show that the vessels in front of the valves are distended by 
the blood, which cannot force a passage back through them. 

41. This simple experiment proves that the true direction 
of the venous blood is toward the heart, That the color o\' the 
blood is dark will be evident, if we compare the hand thus 
bound by a cord with the hand not so bound. It also proves 
that the veins lie near the surface, while the arteries are 



40. Valves in the veins ? What arc they ? Their position ? Experiment with the eord ; 

41. What will be proved by the experiment ? What int'erenee is draw n : ; 



172 THE CIRCULATION 

beneath the muscles, well protected from pressure; and that 
free communication exists from one vein to another. If now 
we test the temperature of the constricted member by means 
of a thermometer, we will find that it is colder than natural, 
although the amount of blood is larger than usual. From this 
fact we infer, that whatever impedes the venous circulation 
tends to diminish vitality ; and hence, articles of clothing or 
constrained postures, that hinder the circulation of the blood, 
are to be avoided as injurious to the health. 

42. The Capillaries. — A third set of vessels completes the 
list of the organs of circulation, namely, the capillary vessels, 
so called (from the Latin word capillaris, hair-like), because of 
their extreme fineness. They are, however, smaller than any 
hair, having a diameter of about T ^~o of an inch, and can only 
be observed by the use of the microscope. These vessels are 
the connecting link between the last of the arteries and the 
first of the veins. The existence of these vessels was unknown 
to Harvey, and was the one step wanting to complete his great 
discovery. The capillaries were not discovered until 1661. 

43. The flow of blood through the veins is dependent upon 
three different forces. First, the pressure from the capillary 
circulation, second, the contraction of the muscles, and third, 
the respiration. The pressure from the capillaries is the re- 
maining impulse originally derived from the heart, and as the 
capillary veins increase in size, from the capillaries toward the 
larger veins, the flow is naturally facilitated. The action of 
the muscles is exerted through their contraction. The veins 
in the arms and legs, as well as in most parts of the body, lie 
between the muscles, so that each contraction of the latter 
squeezes the blood out of the veins and forward toward the 
heart, the valves in them preventing any flow the other way. 
The force exerted through the respiration is during the act of 
inspiration. At this time the chest expands and enlarges in 
all directions, allowing the veins of the thorax to fill more 
readily, and thus making room for the blood in the veins of 
other parts of the body. (Read Note 13.) 

42. Capillaries ? How regarded ? Harvey ? 

43. On what three forces is the flow of blood dependent ? Describe them. 



THE CIRCULATION 



173 



44. The circulation of the blood, as seen under the micro- 
scope, in the transparent web of a frog's foot, is a beautiful 
sight, possessing more than ordinary interest, from the fact 
that something much grander is taking place in our own bodies. 
It is like opening a secret page in the history of our own 
frames. We there see distinctly the three classes of vessels 
with their moving contents ; first, the artery, with its torrent of 
blood rushing down from the heart ; secondly, the vein, with 
its slow, steady stream flowing in the opposite direction ; and 





Fig. 45. — Web of a Frog's Foot, 
slightly magnified 



Fig. 46. — Margin of Frog's Web, 
magnified thirty diameters 



between them lies the network of capillaries, so fine that the 
corpuscles can pass through only "in single file." The current 
of the capillaries has here an uncertain or swaying motion, 
hurrying first in one direction, then hesitating, and turning 
back in the opposite direction, and sometimes the capillaries 
contract so as to be entirely empty. Certain of the tissues are 
destitute of capillaries ; such are cartilage, hair, and a few 
others on the exterior of the body. In all other structures^ 
networks of these vessels are spread out in countless numbers ; 
so abundant is the supply, that it is almost impossible to 
puncture any part with the point of a needle without lacerat- 



44. The circulation of the blood in the web of a frog's fool 1 Describe u. Uvw general 
is the existence of the tissues ? 



174 THE CIRCULATION 

ing tens, or even hundreds of these vessels. (Bead Notes 13 
and 14.) 

45. The capillaries are elastic, and may so expand as to pro- 
duce an effect visible to the naked eye. If a grain of sand, or 
some other foreign particle, lodge in the eye, it will become 
irritated, and in a short time the white of the eye will be 
"blood-shot." This appearance is due to an increase in the 
size of these vessels. A blush is another example of this, but 
the excitement comes through the nervous system, and the 
cause is some transient emotion, either of pleasure or pain. 
Another example is sometimes seen in purplish faces of men 

12. Course of the Blood in the Capillaries. — "The phenomena of 
the capillary circulation are only observable with the aid of the micro- 
scope. It was not granted to the discoverer of the circulation to see the 
blood moving through the capillaries, and he never knew the exact mode 
of communication between the arteries and veins. After it was pretty 
generally acknowledged that the blood did pass from the arteries to the 
veins, it was disputed whether it passed in an intermediate system of ves- 
sels, or became diffused in the substance of the tissues, like a river flow- 
ing between numberless little islands, to be collected by the venous 
radicles and conveyed to the heart. Accurate microscopic investigations 
have now demonstrated the existence, and given us a clear idea of the 
anatomy, of the intermediate vessels. In 1661 the celebrated anatomist 
Malpighi first saw the movement of the blood in the capillaries, in the 
lungs of a frog. This spectacle has ever since been the delight of the 
physiologist. We see the great arterial rivers, in which the blood flows 
with wonderful rapidity, branching and subdividing, until the blood is 
brought to the superb network of fine capillaries, where the corpuscles 
dart along one by one, the fluid then being collected by the veins, and 
carried in great currents to the heart." — Flint. 

13. Experiment. Circulation. — The circulation of the blood can be 
fairly well illustrated by the aid of a " Davidson " syringe, some rubber 
tubing, and a piece of glass tubing. 

The bulb of the syringe represents the heart, the elastic tubing the 
arteries, and the fine glass tubing the capillaries. 

Attach the rubber tubing to the smallest nozzle of the syringe (the 
tubing should be highly elastic, the black kind is the best ; it should be 
about one-fourth inch diameter) , place the other end of the syringe in a 
vessel filled with water. 

Upon compressing the bulb of the syringe, the water will be seen to 
issue from the tubing in jets corresponding with the compressions of the 
bulb, but a little retarded ; placing the ringer on the tubing but little 



4o. Elasticity of the capillaries ? Grain of sand in the eye ? Blush ? Other cases ? 



THE CIRCULATION 175 

addicted to drinking brandy ; in them the condition is a con- 
gestion of the capillary circulation, and is permanent, the ves- 
sels having lost their power of elastic contraction. 

46. Rapidity of the Circulation. — That the blood moves with 
great rapidity is evident from the almost instant effects of cer- 
tain poisons, as prussic acid, which act through the blood. 
Experiments upon the horse, dog, and other inferior animals, 
have been made to measure its velocity. If a substance which 

expansion will be felt. Now into the rubber tube insert the glass tube, 
which should be about two feet long and be drawn out to a fine point. 
Compressing again the bulb of the syringe, the water will be seen to issue 
from the glass point in a continuous stream, and not in an interrupted 
one, as from the rubber end. 

The explanation of this is as follows : During each compression of the 
bulb, the water expands the rubber tubing because its outflow is con- 
siderably lessened by the resistance of the unyielding glass tube and its 
much-narrowed end, and during the interval of two compressions, during 
which the bulb fills again, the rubber tubing contracts upon its contents 
and slowly expels it. If now the compressions of the bulb are so timed 
that the rubber tubing is kept stretched, the flow from the glass-end will 
be continuous. The finger on the tubing will now feel each stroke of the 
syringe in the decided expansion of the rubber. 

Applied to the circulation of the blood, this experiment shows the 
following : 

The power of the hand together with the bulb of the syringe represent 
the heart, which, with each contraction, sends its contents forth into the 
arteries. These are well represented by the elastic tubing, as they, in 
reality, are nothing more than that. During the systole of the heart 
(the compression of the bulb), they are distended to their full capacity ; 
during the diastole of the heart (represented by the passive filling of the 
bulb), they contract upon their contents and send it forward toward the 
capillaries and veins. The latter are represented by the glass tubing, 
from which we have seen the water issue in a continuous stream. In the 
capillaries and veins the blood flows in a continuous stream, due to the 
fact that the force of the heart's action is gradually lost in expanding 
the arteries, and is felt less and less the farther they are removed from 
the heart; the arteries becoming smaller and smaller, the intermittency 
of the flow is lost when the capillaries are reached. 

The expansion which the finger feels when placed upon the rubber 
tubing represents the pulse, which is the maximum distension of the 
artery at that point. 

40. Show what time is required for a given portion of blood to travel once around the 
body. 



176 THE CIRCULATION 

is capable of a distinct chemical reaction (as potassium ferro- 
cyanide, or barium nitrate) be introduced into a vein on one 
side of a horse, and at the end of twenty or thirty-two seconds 
blood be taken from a distant vein on the other side, its 
presence may be detected. In man, the blood moves with 
greater speed, and the circuit is completed in twenty-four 
seconds. 

47. What length of time is required for all the blood of the 
body to make a complete round of the circulation ? This 
question cannot be answered with absolute accuracy, since the 
amount of the blood is subject to continual variations. But, 
if we assume this to be one-eighth of the weight of the body — 
about eighteen pounds — it will be sufficiently correct for our 
purpose. Now to complete the circuit, this blood must pass 
once through the left ventricle, the capacity of which is two 
ounces. Accordingly, we find that, under ordinary circum- 
stances, all the blood makes one complete rotation every two 
minutes — passing successively through the heart, the capil- 
laries of the lungs, the arteries, the capillaries of the extremi- 
ties, and through the veins. 

48. That portion of the blood which passes through the 
spleen, pancreas, stomach, and intestines differs from the rest 
of the blood in that it has to pass through the liver. This is 
known as the portal division, while that passing through the 
lungs is the pulmonary division, and that through the rest of 
the body the systemic division. All the blood coming from 
the organs above enumerated is collected by the veins, which 
unite to form what is called the portal vein. From here the 
blood, filled with all the products of digestion, passes through 
the cells of the liver, where all the glucose is abstracted from 
the blood and stored up as glycogen. The blood is then col- 
lected in a second set of capillaries, which go to form the 
hepatic vein ; and this in turn conveys the blood to the 
inferior vena cava, and so on to the right auricle. The liver 
itself is nourished by fresh arterial blood through the hepatic 



47. Time required for all the blood in the body to circulate completely around ? 

48. What can you say of the blood which passes through the liver? 



THE CIRCULATION 177 

artery, which blood, after it has passed through the capillaries, 
mingles with the blood of the portal capillaries, and is by them 
returned to the heart through the hepatic vein. 

49. Assimilation. — The crowning act of the circulation — 
the furnishing of supplies to the different parts of the body — 
is effected by means of the capillaries. The organs have been 
wasted by use ; the blood has been enriched by the products 
of digestion. Here, within the meshes of the capillary net- 
work, the needy tissues and the needed nutriment are brought 
together. By some mysterious chemistry, each tissue selects 
and withdraws from the blood the materials it requires, and 
converts them into a substance like itself. This conversion 
of lifeless food into living tissue is called assimilation. The 
process probably takes place at all times, but the period espe- 
cially favorable for it is during sleep. Then the circulation is 
slower and more regular, and most of the functions are at 
rest. The body is then like some trusty ship, which, after a 
long vogage, is " hauled up for repairs." {Read Note 15.) 

50. Lymph and the Lymphatic System. — As the blood circu- 
lates through the capillaries of the body, a good deal of its 
liquid portion, the plasma, passes through the walls of the 
capillaries into the surrounding tissue cells. This plasma is 

14. Assimilation in Repair. — " Most animals have the power to 
repair, to a greater or less extent, the mutilations they undergo. In 
man, if the skin is torn off, a new skin heals over the injury, and a broken 
bone is caused to re-unite by the deposit of bone tissue between the frag- 
ments. But among the lower animals this power is carried to a high 
degree. The tail of a lizard, if cut off, will quickly form anew, although 
of a complex structure ; and spiders and crabs are able to develop new 
claws upon the stumps of broken ones. Observations made on salaman- 
ders, or water-lizards, show the still more remarkable fact that the eye 
and a part of the head may be entirely restored. Certain kinds of earth- 
worms can reproduce a large portion of their bodies, and any fragment of 
the hydra is able to restore itself, and become a complete creature after its 
kind. Assimilation is especially active in early years, while the body is 
growing ; for this reason, among others, the perfect health of children 
requires that they shall give a greater number of hours to sleep — deep, 
regular, and undisturbed sleep — than is needed in later life." — Milin 
Edwards. 



-ID. What is stated of the Injuries to the blood-veaaela ? 
50. How duos alcohol affect the heart's action 1 



178 THE CIRCULATION 

here called lymph, and conveys nourishment to the cells ; the 
latter being bathed constantly by the lymph, extract therefrom 
what they require for nourishment, and excrete into it their 
waste materials. The lymphatic system begins in irregular 
spaces between the cells, which gradually unite to form small 
lymph capillaries, which gradually increase and unite to form 
larger and larger vessels, which finally end in the large thoracic 
duct. This duct ascends through the abdomen and chest to 
the root of the neck, where it is joined by lymphatics from the 
left side of the head and the left upper extremity, and empties 
itself into the left subclavian vein. 

51. The lymphatic vessels from the right side of the head and 
neck, and the right upper extremity, form the right lymphatic 
duct which terminates in the right subclavian vein. Thus the 
lymph collected from the tissues of the entire body is mingled 
with the venous blood a little before its arrival at the right side 
of the heart. Along the course of the lymphatic vessels through- 
out the body are found numerous glands, called lymphatic 
glands, through which the lymph percolates in its flow toward 
the heart. The function of these glands is not definitely 
known, but they are supposed to produce the white globules 
of the blood, as they contain numerous cells in structure 
and appearance identical to them. The lymphatic vessels are 
supplied with numerous valves, in structure like those of the 
veins, and the flow of lymph through the lymphatic system is 
dependent upon the same causes which govern the flow of 
blood through the veins. 

52. Injuries to the Blood-vessels. — It is important for us to 
be able to discriminate between an artery and a vein, in the 
case of a wound, and if we remember the physiology of the 
circulation we may readily do so. For, as we have already 
seen, hemorrhage from an artery is much more dangerous than 
that from a vein. The latter tends to cease spontaneously 
after a short time. The arterial blood flows away from the 
heart with considerable force, in jets, and its color is bright 

51. Describe the right lymphatic duct. 

52. What is stated of the injuries to the blood-vessels ? 



THE CIRCULATION 179 

scarlet. The venous blood flows toward the heart from that 
side of the wound farthest from the heart, its stream being 
continuous and sluggish; its color is dark. In an injury to 
an artery, pressure should be made between the heart and the 
wound, while, in the case of a vein that persistently bleeds, it 
should be made upon the vessel beyond its point of injury. 

53. Effects of Alcohol upon the Heart. — The first symptoms 
after a moderate dose of alcohol is an increase of the heart's 
action, a flushing of the face, a sensation of warmth within, a 
general glow without, and some other appearances of increased 
vitality. The action has been that of a spur or goad. It has 
caused strength to be expended instead of increasing it, and, 
in fact, costs the system whatever amount of force is neces- 
sary to expel it ; so that there is a loss of strength, and not 
a gain. 

54. The late Dr. Parkes made a careful study of the amount 
of strain put upon the heart by alcohol. He found that it 
increased both the number and force of the heart's pulsations. 
The period of rest between the beats is reduced, and, conse- 
quently, the heart's nutrition must be interfered with. He 
estimates, in one set of experiments, that the extra work of 
the heart, induced by alcohol, was equivalent to the lifting of 
15.8 tons one foot daily ; and during two days, 24 tons in excess 
of the regular work. Another experimenter states that he has 
known a single glass of liquor to cause 8000 extra heart-beats, 
equivalent to the unnecessary lifting of 9 tons the distance of 
one foot. Estimated in another way, this amount of overtax 
of the heart is equal to that which takes place, during one day, 
in a person having a fever that raises the pulse six to nine 
beats above the rate of health. 

55. Alcohol as a Fat Producer. — Alcohol is said to diminish 
waste, and to make those " fleshy " who use it. This may well 
be the case in those — and the proportion is not small — who 
are rendered sluggish and sleepy by it. The fat which they 
acquire is the fat of inaction. If we may judge of the true 



58. How does alcohol effect the heart's notion : ; 
64. Describe Dr. Parke's experiment. 



180 THE CIRCULATION 

influence of alcohol by experiments on the lower animals, that 
are compelled to take it pure, we will not grant it any fattening 
power. 

56. There is a certain " fatty degeneration " in man — the 
result of alcohol drinking — that is very disastrous, namely, a 
deposit of fat in the muscles of the body. This is destructive 
or weakening to muscular power, and when it evinces itself in 
the heart, it creates a change that is to be dreaded as sapping 
the strength of the one particular organ that should be strong 
in drinkers. It attacks them at a vital spot. The blood also 
undergoes a fatty change which greatly impairs its work of 
nourishing the body. 

57. Exhaustion Due to Alcohol. — The heart does not become 
habituated to the poison nor become tolerant of it. On the 
contrary, it is set moving, with this abnormal activity, with 
each renewal of the dose. This form of exertion is not exer- 
cise, it is overwork ; it is not strengthening, it is exhausting. 
Very few persons who habitually use alcoholic stimulants are 
aware of the enormous strain that is imposed upon the heart, 
although to those who studiously consider the matter the 
wonder is that this organ is not more rapidly worn out than 
it is, If it were not for the fact that the heart is made of the 
strongest muscular tissue in the body, it would of necessity 
fail from overstrain long before it does. 

58. The condition of the heart, mentioned in the last section, 
is known to physicians as " fatty heart," and in part explains 
why it is that drunkards are so little able to withstand the 
attack of those diseases which are attended by fever. It is a 
well-known fact that they are among the first to succumb to 
cholera and other epidemic diseases. Sunstroke is another 
disorder peculiarly frequent in that class of persons ; and to 
indicate that fact some physicians apply the term " drink- 
stroke " to that disease. 



55. How does alcohol make one fleshy ? 

56. What results ? What chanpe in the blood due to alcohol ! 

57. How is exhaustion due to alcohol ? 

58. What other disorders may be due to alcohoi ? 



THE CIRCULATION 181 

59. Action of Tobacco on the Heart. — Tobacco both quickens 
and enfeebles the heart. In some of those who habitually use 
it, it gives rise to a throbbing or heaving sensation in the 
region of the heart, an exaggerated kind of palpitation ; at 
times, this is so tumultuous that the patient fears lest his last 
hour has come. In other cases, there is a weak and irregular 
heart-beat, caused by tobacco poisoning. This is not so alarm- 
ing to the patient as the condition just mentioned, but is no 
less dangerous and much less easily cured. It is apt to injure 
a man's capacity for business affairs, being repressive of health- 
ful energy and exertion. 



5SJ. What two noticeable effects fvoui tobacco ? 



182 



THE CIRCULATION 



TOPICAL OUTLINE 



HEART 



[ Right Cavity 

\ 

I Left Cavity 



Right Auricle 



CAVITIES OF 
THE HEART 



Vessels 



Left Auricle 



BLOOD- 
VESSELS 



Right auricle ) Between these the tri- 
Right ventricle ) cuspid valve. 
Left auricle ) Between these the bicus- 
Left ventricle ) pid or mitral valve. 
C Thin irregular walls. 

[ Vena cava superior — from upper 
\ parts. 

Vena cava inferior — from lower 
parts. 
| Coronary vein — which returns 
the venous blood from the 
[ heart walls. 
Thick walls. 
Papillary muscles. 
Chordae tendinese. 
Right Ventricle \ Three cusps — form the tricuspid valve. 
f Right pulmonary ) 

artery — toright j Semilunar 
lung. valves just 

Left pulmonary j below junc- 
artery — to left | tion. 
i lung. j 

f Thin irregular walls. 

\ { Right pulmonary vein — from 

right lung. 
Left pulmonary vein — from left 
{ lung. 
{ Very thick walls. 
Papillary muscles. 
Chordse tendinese. 
Two cusps — form the bicuspid or mitral 

valve. 
Vessel — The aorta — to all parts. 
Semilunar valves at its origin. 
Coronary arteries com- ] Supply walls of 
mence just outside the \ heart with 
' semilunar valves. J blood. 

{ Take blood from the heart. 
f 1. Outer areolar. 
! 2. Middle muscular and elastic 

thick. 
[ 3. Inner epithelial. 
I Assist in propelling blood by their elastic 
[ recoil. 

\ Connect small arteries with small veins. 
I Arranged like networks. 
1 Very thin walls. 
I Diameter about 3^5 inch. 
r Convey blood to the heart. 



Vessels 1 



Vessels { 



Left Ventricle 



Arteries 



Capillaries 



Coats . i 



Veins 



Coats — same as in arteries, but less mus- 
^ cular and elastic tissue. 
I Generally provided with valves — like the 
i semilunars. 



THE CIRCULATION 



183 



' Auricular 
Contraction 



Ventricular 
Contraction 



ACTION OF 
THE HEART 



Beating 



Sounds 



Simultaneous. 

Blood forced into ventricles. 
Force not sufficient to cause regurgitation 
into the veins. 
C Valves between the auricles and ventricles 

closed. 
| Chorclse tendinese tightly stretched. 
I Semilunars forced open. 

< Blood forced into the great arteries. 
Apex of heart tilted forward against the 

front wall of the chest. 
From 60 (old age) to 120 (young child) per 

< minute. 

( Dull sound — closure of tricuspid and mitral 
valves, and contraction of ventricles (?). 

| Sharp sound — sudden closure of semilu- 
nars. 



Followed by a pause. 



CIRCULATION . 



In Arteries 



In Capillaries 



In Veins 



I Causes 



In jerks (pulsations). 

Very rapid. 

Elastic recoil tends to produce a continuous 
stream in the smaller arteries. 
r Very slow and uniform. 
] Great resistance offered by the capillary 
I walls. 

( Much faster than in capillaries. 
j Not so rapid as in arteries. 
I Steady flow. 

I Valves prevent backward flow. 
( Heart. 

"! Muscular action. 
y Respiration. 



COURSE OF 
THE BLOOD 



' Right auricle. 
Right ventricle. 
Pulmonary arteries. 
Lungs (capillary system) . 
Pulmonary veins. 
Left auricle. 
Left ventricle. 
Aorta. 

Capillary networks in all parts. 
Vena; cavre. 
Right auricle. 
Capillaries of spleen, pancreas. 

stomach, intestines. 
Portal vein. 
Capillaries of liver. 
Hepatic vein. 
Interior vena cava. 
Right auricle. 



Pulmonary Circulation. 



Systemic Circulation. 



Portal Circulation. 



184 



THE CIRCULATION 



Plasma 



COMPOSITION 
OF THE 
BLOOD 



I Corpuscles 



f The liquid of the blood. 
f Water. 

J Dissolved albumen. 
1 | Mineral salts. 



Contains 



{ Red 



White 



[ The elements of fibrin. 

Discs, round, with concave 
sides. 

Diameter, s^oo inch. 

Thickness, tsJso inch. 

Yellowish, when viewed singly. 

Have a tendency to adhere and 
form piles when the blood is 
drawn. 

Haemoglobin, the oxygen car- 
| rier. 

( Shape constantly varying. 
J Diameter, ^os inch. 
| Transparent, jelly-like. 
[ One to every 300 red.* 



CLOTTED 
BLOOD 



( Water. 
Serum . . . <{ Dissolved mineral salts. 

I Dissolved albumen. 
Fibrin . . . Formed during ] 

coagulation. }■ Clot — floats in the serum. 
Corpuscles . . Red and white. J 



BLOOD 



f Arterial 



Venous 



Temperature 
Quantity . 



C Bright red. 

{ Bed in oxygen. 

[ Usually contained in arteries. 

' Dark purple. 

Usually found in veins. 

Less oxygen than arterial blood. 
More carbonic acid gas. 

Converted into arterial blood by absorp- 
[ tion of oxygen . 

99° F. 

One-tenth the weight of the body. 



Contains 



LYMPH 



f Source 

! Uses . 



Apparatus 



Causes of 
[ Circulation 



Plasma of blood by osmosis. 
| Nourish. 
• Excrete. 

f Lymphatic capillaries. 
! Lymphatic ducts. 
I Thoracic duct. 
*• Lymphatic glands, 
j Muscular action. 
/ Respiration. 



THE CIRCULATION 185 

TABLE OF THE PRINCIPAL ARTERIES 

(See Plate opposite Page 145) 



The Head 



Internal Ca-rot'id, [ g , the brain 
Ver te-bral, J 

Oph-thal'n c, supplies the eye. 

External Ca-rot'id f ^ n 'Z u ? ' su Pf es ^e tongue. 

ff < Fa ci-al, supplies the lower part of the face. 

'I Tem'po-ral, supplies the upper part of the head and face. 

The Trunk 

The A-or'ta, arising from the heart, is the main arterial trunk. 

Cor'o-na-ry, supplies the walls of the heart. 

Bron'chi-al, supplies the lungs. 

In-ter-cos'tals, supply the walls of the chest. 

Gas'tric, supplies the stomach. 

He-pat'ic, supplies the liver. 

Splen'ic, supplies the spleen. 

Re'nal, supplies the kidney. 

Mes-en-ter'ics, supply the bowels. 

Spi'nal, supplies the spinal cord. 

The Upper Limb 

Branches of the Ax-il-la'ry, supply the shoulder. 

" " Bra'chi-al, supply the arm. 

(< n Ra'di-al 1 

' [ supply the forearm and ringers. 
" " Ul nar, j * l J 



The Lower Limb 

Branches of the Fem'o-ral, supply the hip and thigh. 
" " Pop-li-te'al, \ 

" " Tib'i-al, > supply the leg and foot. 

" " Per-o-ne'al, J 



QUESTIONS FOR TOPICAL REVIEW 

PACK 

1. In what organisms is the so-called circulatory fluid found ? 152 

2. How is it designated in the different organisms ? 152 

.'*. What can you state of the importance of blood to the body ? 152 

4. Of its great abundance, color, and composition ? 152, 153 

5. Describe the corpuscles of the human blood 153, IM 

(>. What is said of them in comparison with those of the lower animals ? 153 

7. Of the importance of sometimes detecting human from other blood'.' 153 

8. What means have we of detecting blood in spots or stains ? 153 

9. What is meant by coagulation of the blood ? 155 



186 THE CIRCULATION 



PAGE 

10. What wisdom is there in the law of the hlood's coagulation ? 155, 156 

11. How is this wisdom made manifest ? 156 

12. In what cases is the aid of the surgeon required ? 156 

13. What are the two great uses of the blood ? 156, 157 

14. Through what mediums is the blood provided with new material and 

relieved of the old material ? 157 

15. What do you understand by the operation called transfusion ? 157 

16. What cases of transfusion are reported of the lower animals ? 158 

17. What can you state of transfusion as practised upon man ? 157, 158 

18. What further can you say on the subject ? 158 

19. What changes take place in the color of the blood in its journey 

through the system ? 158 

20. State all you can in relation to the circulation of the blood 159 

21. All, in relation to the size, shape, and location of the heart 160, 161 

22. How is the loss of power in the heart-movements obviated ? 161 

23. Give a description of the formation of the heart 161 

24. What can you state of the ventricles and auricles of the heart ?. . . . 161 

25. Describe the action of the heart 162 

26. What special vitality does the tissue of the heart possess? 163 

27. State all you can on the subject 163 

28. Describe the course of the blood through the cavities of the heart. 163, 164 

29. Describe the mechanism that regulates the heart-currents 164 

30. How do you account for the two heart-sounds at the front of the 

chest ? 164 

31. State what you can of the frequency of the heart's action 164, 165 

32. Of the activity of the heart 166, 167 

33. What do you understand by the arteries ? 167, 168 

34. State what you can of the arteries and the arterial system 168 

35. What do you understand by the pulse ? 169, 170 

36. In what part of the body may the pulse be felt ? 169 

37. What further can you state of the pulse ? 169 

38. What are the veins ? 170 

39. Where do they exist, and how are they formed ? 170 

40. Describe the valves of the veins and their uses 171, 172 

41. Now give a full description of the construction of the veins 171, 172 

42. What further can you state of the veins ? 172 

43. What do you understand by the capillaries ? 172 

44. What service do the capillaries perforin ? 173, 174 

45. What can you state of the rapidity of the blood's circulation ? . . . 175, 176 

46. Of the process known as assimilation ? 177 

47. Of injuries to the blood-vessels ? 178 

48. What is the effect of alcohol upon the heart ? 179, 180 

49. What is said of alcohol as a fat-producer ? 180 



CHAPTER VIII 

RESPIRATION 

The Objects of Bespiration — The Lungs — The Air-passages — The 
Movements of Bespiration — Expiration and Inspiration — The Fre- 
quency of Bespiration — Capacity of the Lungs — The Air we Breathe 
— Changes in the Air from Bespiration — Changes in the Blood — 
Interchange of Gases in the Lungs — Comparison between Arterial 
and Venous Blood — Bespiratory Labor — Impurities of the Air — 
Dust — Carbonic Acid — Effects of Impure Air — Nature's Frovision 
for Burifying the Air — Ventilation — Animal Heat — Spontaneous 
Combustion 

1. The Object of Respiration. — In one set of capillaries, or 
hair-like vessels, the blood is impoverished in order to support 
the different members and organs of the body. In another 
capillary system the blood is refreshed and again made fit to 
sustain life. The former belongs to the greater or systemic cir- 
culation ; the latter to the lesser or pulmonary, so called from 
pulmo, the lungs, in which organs it is situated. The blood, as 
sent from the right side of the heart to the lungs, is venous, 
dark, impure, and of a nature hurtful to the tissues. But, 
when the blood returns from the lungs to the left side of the 
heart, it has become arterial, bright, pure, and no longer injuri- 
ous. This marvellous purifying change is effected by means 
of the very familiar act of respiration, or breathing. 

2. The Lungs. — The lungs are the special organs of respi- 
ration. There are two of them, one on each side of the chest, 
which cavity they, with the heart, almost wholly till. The 
lung-substance is soft, elastic, and sponge-like. Cinder pres- 
sure of the finger, it crepitates, or crackles, and floats when 



1. Difference between the two sets of capillaries : ; Change effected by respiration or 
breathing? 

'1. What are the lungs? How many lungs are there? Lung-substanoe ? Its proper- 
ties •'. The pleura ? 

1ST 



188 



RESPIRATION 



thrown into water ; these properties being due to the presence 
of air in the minute air-cells of the lungs. To facilitate the 
movements necessary to these organs, each of them is provided 
with a double covering of an exceedingly smooth and delicate 
membrane, called the pleura. One layer of the pleura is 




Fig. 47. — Organs of the Chest 



A, Lungs 

B. Heart 



D, Pulmonary Artery 

E, Trachea 



attached to the walls of the chest, and the other to the lungs ; 
and they glide, one upon the other, with utmost freedom. 
Like the membrane which envelops the heart, the pleura 
secretes its own lubricating fluid, in quantities sufficient to 
keep it always moist. 

3. The Air-Passages. — The lungs communicate with the 
external air by means of certain air-tubes, the longest of 
which — the trachea, or windpipe — runs along the front of 



3. Communication of the lunjrs with the external air '? Bronchial tubes ? 



RESPIRATION 



189 



the neck (Fig. 47, E, and 48). Within the chest this tube is 
divided into two branches, one entering each lung; these in 
turn give rise to numerous branches, or bronchial tubes, as 
they are called, which gradually diminish in size until they 
are about one twenty-fifth of an inch in diameter. Each of 
these terminates in a cluster of little pouches, or "air-cells," 
having very thin walls, and covered with a capillary network, 
the most intricate in the body (Fig. 49). 

4. These tubes are somewhat flexible, sufficiently so to bend 
when the parts in which they are situated move , but they are 





FiO. 48. — Larynx, Trachea, and 
Bronchial Tubes 



Fig. 49. — Diagram and Section OF 
the Air-cells 



greatly strengthened by bands or rings of cartilage which keep 
the passages always open ; otherwise there would be a con 
stantly-recurring tendency to collapse after every breath. The 
lung-substance essentially consists of these bronchial tubes 
and terminal air-cells, with the blood-vessels ramifying about 
them (Fig. 50). At the top of the trachea is the larynx, a 
sort of box of cartilage, across which are stretched the vocal 



4, Office of the bronchial tubes ) What further can you state of them | 



190 



RESPIRATION 



cords. Here the voice is produced chiefly by the passage of the 
respired air over these cords, causing them to vibrate (Fig. 51). 

5. Over the opening of the larynx is found the epiglottis, 
which fits like the lid of a box at the entrance to the lungs, 
and closes during the act of swallowing, so that food and 
drink shall pass backward to the oesophagus, or gullet (Fig. 
51). Occasionally it does not close in time, and some sub- 
stance intrudes within the larynx, when we at once discover, 
by a choking sensation, that " something has gone the wrong 




way," and, by coughing, we attempt to expel the unwelcome 
intruder. The epiglottis is one of the many safeguards fur- 
nished by nature for our security and comfort, and is planned 
and put in place long before these organs are brought into 
actual use in breathing and in taking food. 

6. The air-passages are lined throughout almost their whole 
extent with mucous membrane, which keeps them in a con- 



5. The epiglottis ? When it does not close in time, what is the consequence ? 

6. Lining of the air-passages ? Ciliated cells ? Their uses ? The three diseases of the 



RESPIRATION 



191 



stantly moist condition. This membrane has cells of a 
peculiar kind upon its outer surface. If examined under a 
powerful microscope, we may see, even for a considerable time 
after their removal from the body, that these cells have minute 
hair-like processes in motion, which wave like a field of grain 




FlG. 51. — Skotion of the Mouth and Throat 



A, The Tongue 

B, The Uvula 



C, Vocal Cord 
E, Epiglottis 
L, Larynx 



N, Trachea 
o, (Esophagus 



under the influence of a breeze (Fig. 52). This is a truly 
beautiful sight; and since it is found that these little cilia, as 
they are called, always produce currents in one direction — 
from within outward — it is probable that they serve a useful 
purpose in catching and carrying away from the Lungs dust 



192 



RESPIRA TION 






and other small particles drawn in with the breath (Fig. 52). 
The three diseases which more commonly affect the lungs, as 
the result of exposure, are pneumonia, or inflammation of the 
lungs, affecting, principally, the air-cells ; bronchitis, an inflam- 
mation of the large bronchial tubes ; and pleurisy, an inflamma- 
tion of the pleura, or outside wrapping of the lungs. Among 
the young, an inflammation of the trachea takes place, known 
as croup. 

7. The Movements of Respiration. — The act of breathing has 
two parts — (1), inspiration, or drawing air into the lungs, and 
(2), expiration, or driving it out again. In inspiration, the 

chest extends in its length, breadth, 
and height. The motion outward and 
upward can be observed every time 
we draw a full breath ; and is caused 
by a lifting of the ribs. But the mo- 
tion downward is not so apparent, as 
it is caused by a muscle within the 

Fig. 52. -Ciliated Cells highly bo^y called the dkwliraqm. This is 

MAGNIFIED . _ . . . , • , , 

the thin partition which separates the 
chest from the abdomen, rising like a dome within the chest 

(Fig. 22). 

8. With every inspiration the diaphragm contracts, and in 
so doing, approaches more nearly a level surface, and thus 
enlarges the capacity of the chest. Laughing, sobbing, and 
sneezing are due to sudden action of the diaphragm. On the 
proper acting of this muscle depends our power to breathe 
deeply; and like other muscles, its strength is increased by 
exercise. This gives that endurance, or "long wind," as it is 
commonly called, which is possessed in a marked degree by 
the mountaineer, the oarsman, and the trained singer. The 
habit of taking frequent and deep inspirations, in the erect 
position, with the shoulders thrown back, tends greatly to 
increase the capacity and power of the organs of respiration. 




7. The act of breathing ? Extension of the chest by breathing ? 

8. Contraction of the diaphragm ? Power of the diaphragm ? Effects of extending the 
walls of the chest ? The habit of taking frequent and deep inspirations ? 



RESPIRATION 193 

9. Expiration is a less powerful act than inspiration. The 
diaphragm relaxes, and ascends in the form of a dome; the 
ribs descend and contract the chest; while the lungs them- 
selves, being elastic, assist to drive out the air. The latter 
passes out through the same channels by which it entered. 
At the end of each expiration there is a period of repose, last- 
ing about as long as the period of action. 

10. Frequency of Respiration. — It is usually estimated that 
we breathe once during every four beats of the heart, or about 
eighteen times in a minute. There is, of course, a close rela- 
tion between the heart and lungs, and whatever modifies the 
pulse, in like manner affects the breathing. When the action 
of the heart is hurried, a larger amount of blood is sent to the 
lungs, and, as a consequence, they must act more rapidly. 
Occasionally, the heart beats so very forcibly that the lungs 
cannot keep pace with it, and then we experience a peculiar 
sense of distress from the want of air. This takes place when 
Ave run until we are "out of breath." At the end of every 
fifth or sixth breath, the inspiration is generally longer than 
usual, the effect being to change more completely the air of 
the lungs. {Bead Note 1.) 

1. Experiment. The Lungs — Respiration. — Obtain from your 
butcher a pair of sheep's or calf's lungs ; they should be cut out with 
great care, so as not to be injured in any part. Insert the nozzle of a 
pair of bellows into the trachea and tie it securely ; then inflate the lungs 
fully, and tie the trachea just below the point of the nozzle very securely, 
so that no air escapes. Now hang the lungs up to dry. If there is no 
hole in any part of them, they will retain the air sufticiently long to allow 
the air-cells to dry in this distended state. During the drying the lungs 
will shrink somewhat, but that will not interfere with the demonstration 
of the specimen. When thoroughly dry, cut through both lungs length- 
wise {see Fig. 50, page 180) with a long, sharp knife. You will then obtain 
a very interesting and valuable specimen, which will keep tor a long time 
if protected from dust. It shows the trachea and its structure, bronchi 
and their subdivision, and the terminal air-cells. 

The presence of carbonic acid gas in the expired air may be demon- 
strated by blowing air through some perfectly clear lime water, by means 
of a glass tube. Carbonic aeid gas produces a chemical change in the 
lime contained in the water, transforming it into carbonate of lime, which 



t). Expiration ? The mechanism of expiration * 
li). Frequency of respiration ? Effeot of hurried action of the heart 



194 RESPIRATION 

11. Although, as a general rule, the work of respiration goes 
on unconsciously and without exertion on our part, it is, never- 
theless, under the control of the will. "We can increase or 
diminish the frequency of its acts at pleasure, and we can 
"hold the breath," or arrest it altogether for a short time. 
From twenty to thirty seconds is ordinarily the longest period 
in which the breath can be held ; but if we first expel all the 
impure air from the lungs, by taking several very deep inspira- 
tions, the time may be extended to one and a half or even two 
minutes. This should be remembered, and acted upon, before 
passing through a burning building, or any place where the air 
is very foul. The arrest of the respiration may be still further 
prolonged by training and habit. It is said that the pearl- 
fishers of India can remain three or four minutes under water 
without being compelled to breathe. 

12. Capacity of the Lungs. — The lungs are not filled and 

emptied by each respiration. For while their full capacity, in 
the adult, is three hundred and twenty cubic inches, or more 
than a gallon, the ordinary breathing air is only one-sixteenth 
part of that volume, or twenty cubic inches — being two-thirds 
of a pint. Accordingly, a complete renovation, or rotation, of 
the air of the lungs does not take place more frequently than 
about once a minute ; and by the gradual introduction of the 
external air, its temperature is considerably elevated before it 
reaches the delicate capillaries that surround the air-cells. In 
tranquil respiration, less than two-thirds of the breathing power 
is called into exercise, leaving a reserve capacity of about one 
hundred and twenty cubic inches, equivalent to three and one- 
half pints. This provision is indispensable to the continua- 
tion of life ; otherwise, a slight interference with respiration 
— by an ordinary cold, for instance — would suffice to cut 

is insoluble in water. After the air has been blown through for a few 
minutes, the water becomes turbid, and after a longer time, milky. Upon 
standing, this milkiness subsides to the bottom in the form of a fine pow 
der, carbonate of lime. 

11. Respiration controlled by the will ? Advantage of the knowledge to us ? 

12. Capacity of the lungs ? Time required to renovate the air in the lungs ? In tran- 
quil respiration ? Importance of the provision ? 



RESPIRATION 195 

off the necessary air, and the spark of life would be speedily 
extinguished. 

13. The Air we Breathe. — The earth is enveloped on all 
sides by an invisible fluid, called the atmosphere. It forms a 
vast ocean of air, forty-five miles deep, encircling and per- 
vading all objects on the earth's surface, and is absolutely 
essential for the preservation of all vegetable and animal life 
— in the sea, as well as on the land and in the air. At the 
bottom, or in the lower strata of this ocean of air, we move 
and have our being. Perfectly pure water will not support 
marine life, for a fish may be drowned in water from which 
the air has been exhausted, just as certainly as a mouse, or 
any other land animal will perish if held under water for a 
short time. The cause is the same in both cases — the animal 
is deprived of the requisite amount of air. It is also stated, 
that if the water-supply of the plant be deprived of air, its 
growth is checked. {Bead Note 2.) 

14. The air is not a simple element, as the ancients sup- 
posed, but is formed by the mingling of two gases, known to 

2. The Atmosphere. — "It surrounds us on all sides, yet we see it not ; 
it presses on us with a load of fifteen pounds to every square inch of sur- 
face of our bodies, or from seventy to one hundred tons on us in all, yet 
we do not so much as feel its weight. Softer than the softest down — 
more impalpable than the finest gossamer — it leaves the cobweb undis- 
turbed, and scarcely stirs the lightest flower that feeds on the dew- it sup- 
plies ; yet it bears the fleets of nations on its wings around the world, 
and crushes the most refractory substances beneath its weight. When in 
motion, ite force is sufficient to level the most stately forests with the 
earth ; to raise the waters of the ocean into ridges like mountains, and 
dash the strongest ships to pieces like toys. It bends the rays of the sun 
from their path, to give us the twilight of evening and of dawn ; it dis- 
perses and refracts their various tints, to beautify the approach and 
retreat of the orb of day. But for the atmosphere, sunshine would burst 
on us and fail us at once, and at once remove us from midnight darkness 
to the blaze of noon. We should have no twilght to soften and beautify 
the landscape, no clouds to shade us from the scorching heat ; but the 
bald earth, as it revolved on its axis, would turn its tanned and weakened 
front to the full and unmitigated rays of the lord of day." — Bxtish. 



18. The atmosphere ? How high or deep ? How essential to life ? Marine life in per- 
fectly pure water and air ? 

14. Composition of the air ? Properties of the two gases ? 



196 RESPIRATION 

the chemist as oxygen and nitrogen, in the proportion of one 
part of the former to four parts of the latter. These gases are 
very unlike, being almost opposite in their properties : nitrogen 
is weak, inert, and cannot support life : while oxygen i§ power- 
ful, and incessantly active, and is the essential element which 
gives to the atmosphere its power to support life and com- 
bustion. The discovery of this fact was made by the French 
chemist, Lavoisier, in 1778. 

15. Changes in the Air from Respiration. — Air that has been 
once breathed is no longer fit for respiration. An animal con- 
fined within it will soon die ; so, also, a lighted candle placed 
in it will be at once extinguished. If we collect a quantity of 
expired air and analyze it, we shall find that its composition 
is not the same as that of the inspired air. \Yhen the air 
entered the lungs it was rich in oxygen ; now it contains 
twenty-five per cent, less of that gas. Its volume, however, 
remains nearly the same — its loss being made up by another 
and very different gas, which the lungs exhale, called carbonic 
acid gas, or, as the chemist terms it, carbon dioxide. 

16. The expired air has also gained moisture. This is no- 
ticed when we breathe upon a mirror or the window-pane, the 
surface being tarnished by the condensation of the watery vapor 
given off by the lungs. In cold weather, this causes the fine 
cloud which is seen issuing from the nostrils or mouth with each 
expiration, and contributes in forming the feathery crystals of 
ice which decorate our window-panes on a winter's morning. 

17. This watery vapor contains a variable quantity of ani- 
mal matter, the exact nature of which is unknown ; but when 
collected it speedily putrefies and becomes highly offensive. 
"From the effects, upon small animals, of confinement in their 
own exhalations, having at the same time an abundant supply 
of fresh air, it is believed that the organic matters thrown off 
by the lungs and skin are direct and active poisons ; and that 

15. Air once breathed? An animal in it ? A candle? Analysis of expired air? 
Change in volume. ? 

16. What else has the expired air gained ? When and where noticed ? . .. ' ._.. 
IT. Nature of the watery vapor ? Its effects upon animals ? '. • . 



RESPIRATION 197 

to such emanations from the body, more than to any other 
cause, are due the depressing and even fatal results which 
follow the crowding of large numbers of persons into places 
of limited capacity. {Bead Note 3.) 

18. History furnishes many painful instances of the ill 
effects of overcrowding. In 1756, of one hundred and forty- 
six Englishmen imprisoned in the Black Hole of Calcutta, 
only twenty-three, at the end of eight hours, survived. After 
the battle of Austerlitz, three hundred prisoners were crowded 
into a cavern, where, in a few hours, two-thirds of their num- 

3. The Two Breaths. — " Every time you breathe, you breathe two 
different breaths : you take in one, you give out another. The compo- 
sition of those two breaths is different. Their effects are different. The 
breath which has been breathed out must not be breathed in again. To 
tell you why it must not would lead me into anatomical details, not quite 
in place here as yet ; but this I may say : those who habitually take in 
fresh breath will probably grow up large, strong, ruddy, cheerful, active, 
clear-headed — fit for their work. Those who habitually take in the 
breath which has been breathed out by themselves, or any other living 
creature, will certainly grow up — if they grow up at all — small, weak, 
pale, nervous, depressed, unfit for work, and tempted continually to 
resort to stimulants and become drunkards. 

• " If you want to see how different the breath breathed out is from the 
breath taken in, you have only to try a somewhat cruel experiment, but 
one which people too often try upon themselves, their children, and their 
work-people. If you take any small animal with lungs like your own — 
a mouse for instance — and force it to breathe no air but what you have 
breathed already ; if you put it in a close box, and, while you take in 
breath from the outer air, send out your breath through a tube into that 
box, the animal will soon faint ; if you go on long with this process, he 
will die. * * * * What becomes of this breath which passes from 
your lips ? Is it merely harmful, merely waste ? God forbid ! God has 
forbidden that anything should be merely harmful or merely waste in this 
so wise and well-made world. The carbonic acid gas which passes from 
your lips at every breath is a precious boon to thousands of tilings of 
which you have daily need. For though you must not breathe your 
breath again, you may at least eat your breath, it you will allow the sun 
to transmute it for you into vegetables ; or you may enjoy its fragrance 
and its color in the shape of a lily or a rose. When you walk in a sun- 
lit garden, every word you speak, every breath you breathe, is feeding 
the plants and dowers around." — Rev. Charles Kingsley on the Two 
Breaths. 



IS. Give some of the instances furnished by history, 



198 RESPIRATION 

ber died. On board a steamship, during a stormy night, one 
hundred and fifty passengers were confined in a small cabin, 
but when morning came, only eighty remained alive. 

19. Changes in the Blood from Respiration. — The most strik- 
ing change which the blood undergoes by its passage through 
the lungs, is the change of color from a dark blue to a bright 
red. That this change is dependent upon respiration has been 
fully proved by experiment. If the trachea, or windpipe, of a 
living animal be so compressed as to exclude the air from the 
lungs, the blood in the arteries will gradually grow darker, 
until its color is the same as that of the venous blood. When 
the pressure is removed, the blood speedily resumes its bright 
hue. Again, if an animal breathes an atmosphere containing 
more oxygen than atmospheric air, the color changes from 
scarlet to vermilion, and becomes even brighter than arterial 
blood. This change of color is not of itself a very important 
matter, but it indicates a most important change of com- 
position. (See Note 4.) 

20. The air, as we have seen, by respiration loses oxygen 
and gains carbonic acid gas ; the blood, on the contrary, gains 
oxygen and loses carbonic acid gas. Oxygen is the food of the 
blood corpuscles ; while the articles we eat and drink go more 
directly to the plasma of the blood. The air, then, it is plain, 



4. Experiment. Changes in the Color of the Blood. — The changes 
produced in the blood by the atmosphere are of easy demonstration 
before a class. Obtain from a butcher some freshly "whipped" blood, 
i.e., blood rapidly stirred with a bundle of twigs while it is being drawn 
from the animal. This removes all the fibrin, and the blood no longer 
coagulates. Upon standing, this gradually assumes a dark-brown color. 

To show that the atmosphere, or rather the oxygen in the atmosphere, 
produces the bright red or arterial blood, fill a pint bottle of white glass 
about one-third full with this dark blood, and shake it briskly ; it will 
very promptly assume a brighter color. The same, or a rather better 
result may be obtained by blowing air through the blood by means of a 
glass tube inserted into the bottle nearly to the bottom. After having 
blown air through for a few minutes, the blood assumes a bright scarlet 
color. Upon standing it again gradually grows dark. 



19. Change in the blood from blue to red. Upon what does the change depend ? How 
shown ? 

20. What does the air lose and gain by respiration ? What, the blood ? Air as food ? 



RESPIRATION 199 

is a sort of food, and we should undoubtedly so regard it, if it 
were not for the fact that we require it constantly, instead of 
taking it at stated intervals, as is the case with our articles 
of diet. Again, as the demand of the system for food is 
expressed by the sensation of hunger, so the demand for air is 
marked by a painful sensation called suffocation. 

21. Interchange of Gases in the Lungs. — But the air and the 
blood are not in contact, as they are separated from each other 
by the walls of the air-cells and of the blood-vessels. How 
then do the two gases, oxygen and carbonic acid gas, exchange 
places? Moist animal membranes have a property which 
enables them to transmit gases through their substance, 
although they are impervious to liquids. This may be beau- 
tifully shown by suspending a bladder containing dark venous 
blood in a jar of oxygen. At the end of a few hours the 
oxygen will have diminished, the blood will be brighter in 
color, and carbonic acid gas will be found in the jar. 

22. If this interchange take place outside of the body, it 
must take place more perfectly within it, where it is favored 
by many additional circumstances. The walls of the vessels 
and the air-cells offer no obstacle to this process, which is 
known as gaseous diffusion. Both parts of this process of 
exchange are equally important. Without oxygen life ceases ; 
if carbonic acid gas is not thrown off, it acts like a poison, pro- 
ducing unconsciousness, convulsions, and death. 

23. Difference between Arterial and Venous Blood. — The fol- 
lowing table presents the essential points of difference in the 
appearance and composition of the blood, before and after its 
passage through the lungs : 

Venous Blood. Arterial Blood. 

Color, Dark blue, Scarlet. 

Oxygen, 8 per cent., 18 per cent. 

Carbonic Acid Gas, 15 to 20 per cent., (i per cent., or less. 

Water, More, Less. 

The temperature of the blood varies considerably; but fche 
arterial stream is generally warmer than the venous. The 

21. Moist animal membranes ? How shown with the bladder? 

22. Gaseous diffusion ? If oxygen be not received ? If carbonic acid be retained ? 

28. Difference in the appearance and composition of the Mood? Temperature of the 
blood ? The blood while passing through the lungs ? The consequence ? 



200 RESPIRATION 

blood imparts heat to the air while passing through the lungs, 
and consequently the contents of the right side of the heart 
have a higher temperature than the contents of the left side.* 

24. By means of the spectroscope, we learn that the change 
of color in the blood has its seat in the corpuscles ; and that, 
according as they retain oxygen, or release it, they present the 
spectrum of arterial or of venous blood. There evidently 
exists, on the part of these little bodies, an affinity for this gas, 
and hence they have been called " carriers of oxygen." It was 
long ago thought that blue blood was peculiar to persons of 
princely or royal descent, and boastful allusions to the "sang 
azure" of kings and nobles are often met with. Physiology, 
however, informs us that blue blood flows in the veins of all — 
the low as well as the high — and really indicates waste and decay. 

25. Respiration of Cells. — The blood of the capillary arteries 
coming from the lungs, where it has been supplied with oxygen, 
passes through the tissues of all parts of the body as already 
stated, and here each cell receives its necessary supply of oxy- 
gen from the blood, and gives up in return carbon dioxide and 
other waste matters, which are then carried through the veins 
to the organs of excretion. 

26. Amount of Respiratory Labor. — During ordinary calm 
respiration, we breathe eighteen times in a minute ; and twenty 
cubic inches of air pass in and out of the lungs with every 
breath. This is equivalent to the use of three hundred and 
sixty cubic inches, or more than ten pints of air each minute. 
From this we calculate that the quantity of air which hourly 
traverses the lungs is about thirteen cubic feet, or seventy-eight 
gallons ; and daily, not less than three hundred cubic feet, or 
nearly sixty barrels. 

27. Of this large volume of air five per cent, is absorbed in 
its transit through the lungs. The loss thus sustained is almost 
wholly of oxygen, and amounts to fifteen cubic feet daily. The 
quantity of carbonic acid gas exhaled by the lungs during the 
day is somewhat less, being twelve cubic feet. Under the in- 

24. What do we learn by means of the spectroscope ? 25. Kespiration of cells ? 

26. Amount of air that passes in and out of the lungs ? 

27. Air absorbed in its transit through the lungs ? 



RESPIRATION 201 

♦ 
fluence of excitement or exertion, the breathing becomes more 

frequent and more profound ; and then the internal respiratory 

work increases proportionately, and may even be double that 

of the above estimate. It has been estimated that in drawing 

a full breath, a man exerts a muscular force equal to raising 

two hundred pounds placed upon the chest. 

28. Impurities of the Air. — The oxygen in the atmosphere 
is of such prime importance, and its proportion is so nicely 
adjusted to the wants of man, that any gas or volatile substance 
which supplants it must be regarded as a hurtful impurity. 
All gases, however, are not alike injurious. Some, if inhaled, 
are necessarily fatal ; arsenuretted hydrogen being one of these, 
a single bubble of which destroyed the life of its discoverer, 
G-ehlen. Others are not directly dangerous, but because they 
take the place of oxygen, and exclude it from the lungs, they 
do harm, and become dangerous. To this latter class belongs 
carbonic acid gas. 

29. Most of the actively poisonous gases have a pungent or 
offensive odor ; and, as may be inferred, most repugnant odors 
indicate the presence of substances unfit for respiration. 
Accordingly, as we cannot see or taste these impurities, the 
sense of smell is our principal safeguard against them. In this 
we recognize the forethought which has stationed this sense, 
like a sentinel, at the proper entrance of the air-passages, to 
give us warning of approaching harm. Take, as an example, 
the ordinary illuminating gas of cities, from which so many 
accidents happen. How many more deaths would it cause if, 
when a leak occurs, we were not able to discover the escape of 
the gas by means of its disagreeable odor. (Bead Notes 5 and (5.) 

5. Cleanliness the Sum Total of Hygiene. — " Disinfectants have 
the power of destroying the cause, and of arresting the spread of most 
epidemics and contagious diseases, but cleanliness is the best preventive 
of disease. Whenever practicable, the abundant use of water is better 
than disinfection. ' Let no one ever depend upon disinfectants, fumiga- 
tions, and the like, for purifying the air. The offensive thing, not its 
smell, must be removed.* " — Florence Nightingale, Notes on Nursing 
(in part). 

28. Importance of the oxygen in the atmosphere ? Injurious character of gases 1 
21). Pungency of gases ? The inference ? Our safeguard I 



202 RESPIKATION 

30. Organic matters exist in increased measure in the ex- 
pired breath of sick persons, and impart to it, at times, a 
putrid odor. This is especially true in diseases which, like 
typhus and scarlet fever, are referable to a blood poison. In 
such cases the breath is one of the means by which nature 
seeks to expel the offending material from the system. Hence, 
those who visit or nurse fever-sick persons should obey the 
oft-repeated direction, "not to take the breath of the sick." 
At such times, if ever, fresh air is demanded, not alone for the 
sick, but also for those who take care of them. (See Care of 
Sick-Room, Appendix.) 

31. Dust in the Air. — Attention has lately been directed to 
the dust, or haze, that marks the ray of sunshine across a 
shaded room. Just as, many years ago, it was discovered that 
myriads of animalcules were found in the water we drank, so 
now the microscope reveals " the gay motes that dance along a 
sunbeam " to contain multitudes of animal and vegetable forms 
of a very low grade — the germs of fermentation and decay, 
and the probable sources of disease. 

32. It is found that the best filter by which to separate this 
floating dust from the air is cotton wool, although a handker- 
chief will imperfectly answer the same purpose. In a lecture 

6. The True Prevention of Epidemics. — "It was in England that 
solution of the great problem of hygiene was first attempted. ' Pre- 
ventive Medicine,' it is there called. Falmerston told a deputation which 
waited on him in order to ask him to order a fast on the approach of the 
second epidemic of cholera, to cleanse their sewers, and diligently visit 
the dwellings of the poor. And he did not confine himself to good advice, 
but, with his usual energy, he laid his hand on sanitary legislation, and 
purified the air of London and the large manufacturing towns. The 
result of the sanitary measures carried out was a reduction of the mor- 
tality of London from 26 to 23 per 1,000, and in some of the towns to 17 
per 1,000 — a low death-rate previously only equalled in the Isle of 
Wight. More than four thousand lives have been preserved yearly in 
London ; and, assuming that the mortality among the sick is 1 in 20, this 
number represents a diminution in yearly sickness to the extent of eighty 
thousand." — Dr. Joseph Seegen in the Vienna Medical Weekly. 



30. The air of rooms in which fever-sick persons are confined ? 

31. Animalcules in the water ? Dust in the*air ? 

32. The best air filter ? The remarks of Prof. Tvndall ? 



RESPIRATION 203 

on this subject by Prof. Tyndall, he remarks that, "by breath- 
ing through a cotton wool respirator, the noxious air of the 
sick-room is restored to practical purity. Thus filtered, attend- 
ants may breathe the air unharmed. In all probability, the 
protection of the lungs will be the protection of the whole 
system. For it is exceedingly probable that the germs which 
lodge in the air-passages are those which sow epidemic disease 
in the body. If this be so, then disease can certainly be 
warded off by filters of cotton wool. By this means, so far as 
the germs are concerned, the air of the highest Alps may be 
brought into the chamber of the invalid." 

33. Carbonic Acid Gas in the Air. — We have already spoken 
of this gas as an exhalation from the lungs, and a source of 
impurity ; but it exists naturally in the atmosphere in the pro- 
portion of one-half part per thousand. In volcanic regions it 
is poured forth in enormous quantities from fissures in the 
earth's surface. Being heavier* than air, it sometimes settles 
into caves and hollows in the surface. It is stated that in the 
island of Java, there is a place called the " Valley of Poison," 
where the ground is covered with the bones of birds, tigers, 
and other wild animals, which were suffocated by carbonic acid 
gas while passing over it. The Lake A vermis, the fabled 
entrance to the infernal regions, was, as its name implies, bird- 
less, because the birds, while flying over it, were poisoned by 
the gas, and fell dead into its waters. In mines, carbonic acid 
gas forms the dreaded choke-damp, while carburetted hydrogen 
is the fire-damp. 

34. In the open air, men seldom suffer from carbonic acid 
gas, for, as we shall see presently, nature provides for its rapid 
distribution, and even turns it to a good use. But its ill effects 
are painfully evident in our homes, schools, and churches, 
where it is liable to collect as the waste product of respiration, 
and of that combustion which is necessary for lighting and 
warming our homes. A man exhales, during repose, not less 
than one-half cubic foot of carbonic acid gas per hour. A single 

88. Carbonic acid in volcanic regions ? In Java? At Lake A vermis ? In mines? 
84. In the open air? Amount of carbonic acid exhaled In a man ? A gas-burner? A 
room fire ? From furnaces ? 



204 RESPIRATION 

gas-burner liberates five cubic feet in the same time, therefore 
spoiling about as much air as ten men. A tire burning in a 
grate or stove emits some impure gases, and at the same time 
abstracts from the air as much oxygen as twelve men would 
consume in the same period, thus increasing the relative 
amount of carbonic acid gas in the air. From furnaces, as 
ordinarily constructed, this and other gases are constantly 
leaking and poisoning the air of tightly-closed apartments. 

35. Effects of Impure Air. — Carbonic acid gas, in its pure 
form, is irrespirable, causing rapid death by suffocation. Air 
containing forty parts per thousand of this gas (the composition 
of the expired breath) extinguishes a lighted candle, and is 
fatal to birds ; when containing one hundred parts, it no longer 
yields oxygen to man and other warm-blooded animals, and is, 
of course, speedily fatal to them. In smaller quantities, this 
gas causes headache, labored respiration, palpitation, uncon- 
sciousness, and convulsions. 

36. In crowded and badly ventilated apartments, the air is 
breathed over until it contains from six to ten times the natural 
amount of carbonic acid gas. This contaminated air causes 
dullness, drowsiness, and faintness, because the dark, impure 
blood circulates through the brain, oppressing that organ, and 
causing it to act like a blunted tool. This is a condition not 
uncommon in our schools, churches, and court-rooms — the 
places of all others where it is desirable that the mind should 
be alert and free to act; but, unhappily, an unseen physio- 
logical cause is at work, dispensing weariness and stupor over 
pupils, audience, and juries. {Bead Xotes 7 and 8.) 

7. The Ground-Atmosphere and its Relations to Dwellings. — "The 
soil, which naturally contains wholesome air, and gives facility to its every 
movement, is not less permeable by poisonous gases, which are often found 
to pervade and issue from it. It is easy to find illustrations of the fact 
that people are poisoned through the ground, since it is almost a daily 
occurrence. Here is one, related by an eminent authority, von Petten- 
kofer : — 'In a residence at Augsburg, apparently endowed with every 
qualification for health and comfort, several priests lived together. On a 



35. Effects of inhaling carbonic acid alone ? In small quantities ? 

36. Effects of the air in crowded and badly-ventilated rooms ? 



RESPIRATION 205 

37. Another unmistakable result of living in and breathing 
foul air is fdtmd in certain diseases of the lungs, especially 
consumption. For many years the barracks of the British 
army were constructed without any regard to ventilation ; and 
during those years the statistics showed that consumption was 
the cause of a very large proportion of deaths. At last the 
government began to improve the condition of the buildings, 

certain morning, one of these, not the least zealous and prompt in the 
performance of his duties, was missed from his usual post at the matin 
service. His colleagues hurried hack to their common dwelling in search 
of the missing priest, and found him lying prostrate and insensible upon 
the floor of his bed-chamber. A doctor was immediately called in, and 
at the first sight of his patient, declared him to be suffering from an attack 
of typhus fever. The Sisters of Charity, upon whom devolved the duty 
of nursing him, and those clerical associates who were active in their 
sympathy and prompt to visit him and give assistance, were, a few hours 
after, attacked in the same way. The doctor did not hesitate in his 
diagnosis, and pronounced the additional cases also typhus fever. A 
general alarm prevailed in the city, and many called at the house of the 
priest, who was greatly beloved. Among others was an old woman, who 
discovered a strong smell of gas, and believing this to be the cause of the 
sickness, obtained permission to remove the priest to her own house. The 
priest had no sooner breathed the fresh air than he began to revive, and 
during the very first evening of his removal to the new abode he became 
so much better as to make an importunate demand for food. He soon 
got entirely well. The old woman, thus confirmed in her gas theory, and 
eager to save the remaining patients, who had continued to increase in 
number in the priests' house, now had an interview with the manager 
of the gas-works which supplied the town, and prevailed upon him to 
investigate the condition of the gas-pipes in the vicinity of the priests' 
residence. This was done, and a leak from which the gas was escaping 
into the ground was found and stopped. The air of the house was per- 
ceived at once to improve, and with it the health of the patients that were 
not removed ; these finally completely recovered from what the doctor even 
was compelled to admit was not typhus fever, but poisoning by gas.' " — 
The Book of Health. 

8. Pure Air and Good Morals. — " Cleanliness and self-respect go to- 
gether, and it is no paradox to affirm that you tend to purify nun's 
thoughts and feelings when you purify the air they breathe. * * * * 
With a low average of popular health you will have a low average of 
national morality, and probably also of national intellect. Drunkenness 
a,nd vice of other kinds will flourish in such a soil, and you cannot get 
healthy brains to grow on unhealthy bodies." Lord Derby. 



37. A cause of consumption ? How was the foot Illustrated 1 



206 RESPIRATION 

giving larger space and air-supply; and as a consequence, 
the mortality from consumption has diminished more than 
one-third. 

38. The lower animals confined in the impure atmosphere 
of menageries, contract the same diseases as man. Those 
brought from a tropical climate, and requiring to be closely 
housed, generally die of consumption. In the Zoological 
Gardens of Paris, this disease affected nearly all monkeys, 
until care was taken to introduce fresh air by ventilation, and 
then it almost wholly disappeared. The tendency of certain 
occupations to shorten life is well known, disease being occa- 
sioned by the fumes and dust which arise from the materials 
employed, in addition to the bad air of the workshop or 
factory, where many hours are passed daily. {Read Note 9.) 

39. The following table shows the comparative amount of 
carbonic acid gas in the air under different conditions, and the 
effects sometimes produced : 

PKOPOETION OF CAKBONIC ACID GAS. In 1000 parts of Air. 

Air of country 4 

Air of city 5 

In hospital, well ventilated 6 

In school, church, etc., fairly ventilated . . . 1.2 to 2.5 
In court-house, factory, etc., without ventilation 4. to 40. 

In bed-room, before being aired 4.5 

In bed-room, after being aired 1.5 

Constantly breathed, causing ill health .... 2. 
Occasionally breathed, causing discomfort ... 3. 
Occasionally breathed, causing distress .... 10. 

Expired air 40. 

Air no longer yielding oxygen 100. 

9. Consumption is Lung Starvation. — "The practice of allowing the 
lungs only improper food, in the form of vitiated air, is one of the most 
prevalent habits of civilized life, and diseases of the lungs are its greatest 
bane and greatest dread. More persons die by consumption than by any 
other single disease. If there be added to those the large number that 
perish every year by inflammation of the lungs and bronchial tubes, disease 
and premature death may be well said to have in these organs their chief 

38. How, in the case of the lower animals ? Tendency of certain occupations ? 
89. Give the fact as set forth in the table. 



RESPIRATION 207 

40. Nature's Provision for Purifying the Air. — We have seen 
that carbonic acid gas is heavier than air, and irrespirable. 
Why, then, does it not sink upon and overwhelm mankind 
with a silent, invisible wave of death? Among the gases 
there is a more potent force than gravity, which forever pre- 
vents such a tragedy. It is known as the diffusive power of 
gases. It acts according to a definite law, and with a resist- 
less energy compelling these gases, when in contact, to mingle 
until they are thoroughly diffused. The added influence of 
the winds is useful, by insuring more rapid changes in the air, 
air in motion being perfectly wholesome. The rains also wash 
the air. 

citadel. The leading cause of all this is, undoubtedly, the poor quality 
of the food on which the lungs are nurtured. The very best physicians, 
when their attention is directed to the subject, admit the full force of 
this conclusion, and that it has not received the attention it deserves. 
Professor Hartshorne remarks on this point, that ' the influence of 
impure air in promoting consumption has probably heretofore been 
underrated. ' ' The vitiated air of the European barrack system for 
soldiers,' says Professor Parkes, 'is the only way. in which the great 
prevalence of consumption in European armies can be accounted for.' 
This is the conclusion to which the Sanitary Commissioners for the army 
came, in their celebrated report : ' A great amount of phthisis (con- 
sumption) has prevailed in the most varied stations of the army and in 
the most beautiful climates — in Gibraltar, Malta, Ionia, Jamaica, Trini- 
dad, Bermuda, etc. — in all of which places the only common condition 
was the vitiated atmosphere which our barrack system everywhere pro- 
duced. And, as if to clinch the argument, there has been of late years a 
most decided decline in phthisis in these stations, while the only circum- 
stance which has notably changed in the time has been the condition of 
the air.' A very eminent authority, the late Dr. Marshall Hall, of Eng- 
land, said, in reference to pure air in the treatment of consumption, ' If 
I were seriously ill of consumption, I would live out doors day and 
night, except in rainy weather, or midwinter ; then I would sleep in 
an unplastered log house. Physic has no nutriment, gaspings for air 
cannot cure you, monkey capers in a gymnasium cannot cure you, and 
stimulants cannot cure you. What consumptives want is pure air, not 
physic — pure air, not medicated air — plenty of meat and bread. 1 Let 
it be remembered, in this connection, that every hygienic or health- pro- 
moting measure which tends to cure a disease is much more efficacious in 
preventing it." — Black's Ten Laws of Health. 



40. What can you state of the diffusive power ofgases? The added Influence of the 
winds ? 



208 RESPIRATION 

41. Oxidation. — When a substance capable of undergoing 
chemical changes unites with oxygen, it is said to oxidize. 
This process of oxidation is always accompanied by the pro- 
duction of heat. As an example, when coal is burned, its 
carbon and other component parts unite with oxygen and form 
new chemical compounds, thus producing a great deal of heat. 
The chemical processes going on during the burning of coal 
set free a certain amount of energy, which is utilized in the 
production of steam and other kinds of power. Thus, in an 
analogous manner, do the chemical processes going on con- 
stantly in our body by the aid of the oxygen produce heat and 
energy. {Bead Xote 15.) 

42. In the sea, as in the air, the same circle of changes is 
observed. Marine animals consume oxygen and give off car- 
bonic acid gas, while marine plants consume carbonic acid gas, 

10. Plants and the Air. — " Though the air is dependent for the renewal 
of its oxygen on the action of the green leaves of plants, it must not be 
forgotten that it is only in the presence and under the stimulus of light 
that these organisms decompose carbonic acid gas. All plants, irrespec- 
tive of their kind or nature, absorb oxygen and exhale carbonic acid gas 
in the dark. The quantity of noxious gas thus eliminated is, however, 
exceedingly small when compared with the oxygen thrown out during the 
day. Aside from the highly deleterious action that plants may exert on 
the atmosphere of a sleeping-room, by increasing the proportion of car- 
bonic acid gas during the night, there is another and more important 
objection to be urged against their presence in such apartments. Like 
animals, they exhale peculiar volatile organic principles, which in many 
instances render the air unfit for the purposes of respiration. Even in 
the days of Andronicus this fact was recognized, for he says, in speaking 
of Arabia Felix, that ' by reason of myrrh, frankincense, and hot spices 
there growing, the air was so obnoxious to their brains, that the very 
inhabitants at some times cannot avoid its influence.' What the influence 
on the brains of the inhabitants may have been does not at present interest 
us ; we have only quoted the statement to show that long ago the emana- 
tions from plants were regarded as having an influence on the condition 
of the air ; and, in view of our present ignorance, it would be wise to banish 
them from our sleeping apartments, at least until we are better informed 
regarding their true properties." — Draper on Poisoned Air. 



41. How is the constant purity of the air secured ? Explain the process. 

42. What process occurs in the sea ? How is the fact illustrated ? 



RESPIRATION 



209 



and liberate oxygen. Taking advantage of this fact, we may 
so arrange aquaria with fishes and sea-plants, in their proper 
combinations, that each may supply the needs of the other, 
and the water may seldom require to be renewed. This affords 
us, on a small scale, an illustration of the grand circle of 
changes taking place in the air about us, and also of the har- 
monious dependence of the two great kingdoms of nature. 

43. Ventilation. — Since the external atmosphere, as pro- 
vided by nature, is always pure, and since the air in our 
dwellings and other buildings is almost always impure, it 
becomes imperative that therfi should be a free communication 
from the one to the other. This we aim to accomplish by venti- 
lation. As our houses are ordinarily constructed, the theory of 
ventilation, "to make the internal as pure as the external air," 
is seldom carried out. Doors, windows, and flues, the natural 
means of replenishing the air, are too often closed, almost 
hermetically, against 
the precious element. 
Special means, or spe- 
cial attention, must 
therefore be used to se- 
cure even a fair supply 
of fresh air. This is 
still more true of those 
places of public resort, 
where large numbers. 
of persons are crowded 
together. (See House- 
Drainage, Appendix.) 

44. If there are two 

openings in a room, one 

as a vent for foid air, 

and the other an inlet 

for atmospheric air, and 

• o ,-1 • i-i Fig. 58. — Showing manner of ventilating by inserting 

II tne openings be large Btrip of wood beneath lower sash of window 




48. Character of the external air ? Of the air in our dwellings ? What becomes impera- 
tive ? Imperfect ventilation of our dwellings : J 

44. What bints are given for the ventilation of our dwellings? 



210 RESPIRA TION 

in proportion to the number of air consumers, the principal 
object will be attained. Thus, a door and window, each open- 
ing into the outer air, will ordinarily ventilate a small apart- 
ment ; or a window alone will answer, if it be open both above 
and below, and the open space at each end be not less than one 
inch for each occupant of the room, when the window is about 
a yard wide. The direction of the current is generally from 
below upward, since the foul, heated air tends to rise 5 but this 
is not essential.* Its rate need not be rapid; a "draught," 
or perceptible current, is never necessary to good ventilation. 
The temperature of the air admitted may be warm or cold. It 
is thought by many that if the air is cold, it is pure ; but this 
is an error, since cold air will receive and retain the same 
impurities as warm air. 

45. Shall we open our bed-rooms to the night air ? Florence 
Nightingale says, in effect, that night air is the only air we 
can then breathe. " The choice is between pure air without 
and impure air within. Most people prefer the latter — an 
unaccountable choice. An open window, most nights in the 
year, can hurt no one. In great cities, night air is the best 
and purest to be had in twenty-four hours. I could better 
understand, in towns, shutting the windows during the day 
than during the night." {Read Note 11.) 

* When the window is of the common sash kind, a good supply of 
fresh air may be obtained without a current, by placing a strip of board 
about four inches wide under the lower sash (Fig. 53). The window is 
thus closed against rain and snow, but allows of a supply of fresh air to 
enter between the sashes. If still more ventilation is needed to keep the 
air of the room sweet, the same arrangement may be made at the top of 
the window. 

11. Pure Air in our Homes during Cold Weather. — " Fresh air is the 
great natural disinfectant, antiseptic, and purifier, and not to be com- 
pared for a moment with any of artificial contrivance. There is plenty of 
it in the world ; yet, disguise the fact as we may, there is no getting over 
the unwelcome truth, that to provide it in abundance in our climate is 
expensive, since during seven months in the year it must be artificially 
warmed, in order that our homes may be comfortable. To take in air at 
the average winter temperature of 28°, raise it to 68 c , and discharge it 



45. State what Florence Nightingale says a'oout inhaling night air. 



RESPIRATION 211 

46. Animal Heat. — Intimately connected with respiration is 
the production of animal heat, or the power of maintaining the 
temperature of the body above that of the medium in which 
the creature moves ; thus, the bird is warmer than the air, and 
the fish than the water. This elevation of temperature is the 
result of the various chemical changes which are constantly 
taking place in the system. Although common to all animals, 
in a greater or less degree, heat is not peculiar to them, since 
plants also generate it, especially at the time of sprouting and 
flowering. If a thermometer be placed in a cluster of geranium 
flowers, it will indicate a temperature several degrees above 
that of the surrounding air. 

47. Among animals great differences are noticed in this 
respect, but the degree of heat produced is always proportional 
to the activity of respiration and the amount of oxygen con- 
sumed. Accordingly, the birds, whose habits are extremely 
active, and whose breathing capacity is the greatest, have uni- 
formly the highest temperature. Sluggish animals, on the 
contrary, as frogs, lizards, and snakes, have little need for 
oxygen, and have incompletely developed lungs ; these animals 
are cold to the touch — that is, they have relatively a lower 
temperature than man, and their positive temperature is but 
little above that of the external air. Accordingly, zoologists 
have so arranged the animal kingdom that warm-blooded ani- 
mals, including man, the birds, and the quadrupeds, are classi- 
fied together; while the cold-blooded animals, such as the fish, 
tortoise, frog, and all that have no vertebral column, are classed 
by themselves. 

again from our houses even once in an hour, is a process which cannot be 
accomplished without paying roundly ; yet on no other condition can we 
reasonably expect health and long life. The best way is to freely admit 
that it is expensive, but worth the money it costs. If Benjamin Franklin 
thought that 'a penny saved is a penny earned,' he is equally sure that 
' health is wealth.' " — George Derby on the Prevention of Disease. 



46. Warmth of the bird as compared with that of the air ? Of the fish and the water ! 
Heat in animals and plants ? How illustrated with the thermometer ? 

47. Amount of heat in animals, how apportioned '? As regards the birds ? Frogs, and 
other sluggish animals ? Arrangement made by zoologists ? 



212 RESPIRA TIOX 

48. The temperature of the human, body is about 100° Fah- 
renheit, and remains about the same through winter and sum- 
mer — in the tropics as well as in the frozen regions of the 
north. It may change temporarily within the range of about 
twelve degrees ; but any considerable, or long-continued eleva- 
tion or diminution of the bodily heat is certain to result dis- 
astrously. 

49. Man is able to adapt himself to all extremes of climate ; 
and, in fact, by means of clothing, shelter, and food, is able to 
create for himself an artificial climate wherever he chooses to 
reside. The power to resist cold consists chiefly in prevent- 
ing the heat which is generated by the vital processes of 
the body from being lost by radiation. Warm clothing, such 
as we wear in winter, has, in reality, the same temperature as 
that which is worn in summer ; but, by reason of being thick 
and porous, it is a bad conductor of heat, and thus prevents the 
escape of that produced by the body. If woollen fabrics were 
intrinsically warm, no one would wrap a piece of flannel, or 
blanket, around a block of ice to prevent its melting in sum- 
mer. 

50. The faculty of generating heat explains how it is that 
we are enabled to resist the effects of cold ; but how does the 
body withstand a temperature higher than its own ? Men have 
been know to remain several minutes in an atmosphere heated 
above the boiling-point of water, and yet the temperature of 
their own bodies was not greatly increased. Those who labor 
in foundries and glass-works are habitually subjected to very 
high degrees of temperature, but they do not suffer in health 
more than those engaged in many other occupations. 

51. The regulation of the temperature of the body is effected 
by means of perspiration, and by its evaporation. So long as 
the skin acts freely, and the air freely absorbs the moisture, 
the heat of the body does not increase, for whenever evapora- 

48. State what is said respecting the temperature of the human body. 

49. Ability of man to adapt himself to different climates? In what does the power to 
resist cold consist ? What is said about warm clothing ? 

50. Men in an atmosphere above the boiling-point ? In foundries and glass-works ? 

51. The regulation of the temperature of the body. * Give the explanation. 



RESPIRATION 213 

tion takes place, it is attended with the abstraction of heat — 
that is, the part becomes relatively colder. This may be tested 
by moistening some part of the surface with cologne, ether, or 
other volatile liquid, and then causing it to evaporate rapidly 
by fanning. The principle that evaporation produces cold has 
been ingeniously and practically employed, in the manufacture 
of ice by means of freezing machines. 

52. Spontaneous Combustion — Alcohol the Indirect Cause. — 

Is it possible that the temperature of the living body can be so 
increased that its tissues will burn spontaneously ? From time 
to time cases have been reported in which, by some mysterious 
means, considerable portions of the human body have been 
consumed, apparently by fire — the victim being found dead, or 
incapable of explaining the occurrence. Hence, the theory has 
been current that, under certain conditions, the tissues of the 
body might become self-ignited ; and the fact that this so-called 
spontaneous combustion has ordinarily taken place in those who 
had been addicted to the use of alcoholic drinks, has given a 
color of probability to the opinion. It has been supposed that 
the flesh of these unfortunate persons, becoming saturated with 
alcohol thus taken into the system, took fire upon being ex- 
posed to a flame, as of a lighted candle, or, indeed, without any 
external cause. But, whether this be possible or not, one thing- 
is certain — this strange kind of combustion has never been 
actually witnessed by any one competent to give a satisfactory 
account of it. 

53. The results that have been observed may be satisfacto- 
rily explained by the accidental ignition of the clothes, or other 
articles near the body, and by the supposition that the indi- 
vidual was at the time too much stupefied by intoxication to 
notice the source of danger and provide for his safety. The 
highest temperature that has been observed in the body — 
about 112° Fahrenheit — is too low to ignite the vapor of alco- 
hol; much less will it cause the burning of animal tissues. It 
is undoubtedly true that when the tissues are tilled with alco- 

52. State what is said of spontaneous combustion, 
68, How is the theory refuted ? 



214 RESPIRATION 

hoi, combustion will more easily take place than when the body 
is in a normal state ; but, under any condition, the combustion 
of the body requires a higher degree of heat than can be gener- 
ated by the body itself, or the mere proximity of a lighted 
candle, or any cause, of similar character. 

54. The Effect of Alcohol upon Respiration. — Whenever wine, 
or any other form of alcoholic drink, is taken into the stomach, 
it is quite rapidly absorbed into the blood-current, and in a few 
minutes it imparts to the breath a peculiar, offensive odor. 
This is due to the vapor of alcohol that, little by little, is ex- 
pelled from the body, along with the carbonic acid gas exhaled 
through the lungs. If the quantity of drink taken has been con- 
siderable, this disagreeable odor may continue a day or more. 

This condition is evidence that an unnatural labor has been 
thrown upon the lungs ; namely, it is an effort on the part of 
the general system to get rid of a poison that is hurtful to every 
organ by which it is retained. While this exhalation of alco- 
holic vapor continues, the respiratory act is impaired, for not 
only can less carbonic acid gas be thrown off, but there is also 
a diminished inhalation of oxygen. 

55. Respiratory Diseases among the Intemperate. — The struc- 
ture of the respiratory organs is such that they are relatively 
tolerant of the presence of alcohol in the body. 

Wheezy breathing and hoarseness of voice are noticeable 
among inebriates ; but this class does not suffer greatly from 
severe attacks of lung diseases that can be said to be directly 
due to the liquor they drink. Indirectly, however, they suffer 
greatly, as a class, from those diseases, because they incur ex- 
posures of every imaginable variety, while under the intoxicant 
influence of this powerful drug, which can, according as it is 
taken in less or greater quantity, deprive a person of his sober 
self-management or bring him down to utter loss of conscious- 
ness. It is in this way that the users of alcohol fall a prey, 
especially in the winter season, to attacks of pneumonia, or 
lung fever, and other serious disease of the respiratory organs. 

54. Does alcohol appear in the breath ? Does it interfere with respiration ? 

55. What respiratory diseases among the intemperate ? 



RESPIRATION 



215 



TRACHEA 



LARYNX 



LUNGS 



INSPIRATION 



EXPIRATION 



CHANGES 



Structure 



Rings . . 
Bronchi . 

Bronchial 
tubes 



Right . , 
Left . 

Vessels 



TOPICAL OUTLINE 

C Cartilaginous rings. 

\ Fibrous tissue. 

I Lined with ciliated epithelium. 

c C-shaped. 

{ Complete in front. Incomplete behind. 

( Connected by fibrous tissue. 

| Right and left. 

j In structure similar to trachea. 

{ Rings of cartilage very imperfect. 

\ Cartilage disappears in smallest lubes 

I which terminate in groups of air-cells. 

f Thyroid cartilage I ^ arge * _ 
Two rings . . { J b i Incomplete behind. 

I Cricoid cartilage — A complete ring. 
Contains . . . \ Vocal cords. 

Epiglottis — Closes the glottis. 

Three lobes. 

Two lobes. 

Air-vessels — Bronchial tribes and cells. 

C Pulmonary arteries. 
Blood-vessels \ Capillaries. 

{ Pulmonary veins. 
External intercostals contract. 
Raise the ribs. 
Chest enlarged \ Make the chest wider. 
j Diaphragm depressed. 
[ Chest made deeper. 
Lungs expand with the chest. 

Air rushes in through the trachea, filling the enlarged lungs 
Elastic walls of the thorax recoil. 
Elastic lungs recoil. 
Internal intercostals con- ) 
tract. 
Chest Ribs depressed, 

made Chest becomes narrower, 

smaller Diaphragm raised. 

Chest made shallower. 
Abdominal muscles contract. 
Abdominal organs press on 
under side of diaphragm. 
Air forced out through the trachea. 
Loses — Oxygen. 

( Carbon dioxide. 



Forced 
expiration. 



Gains 



Blood 



In lungs 



In tissues 



Water vapor. 

Other waste matters. 

(Carbon dioxide. 
Water. 
Other waste matter. 
Gains — Oxygen. 
Loses — Oxygen. 

I Carbon dioxide. 
Gains •! Waste matter in so- 
I lutiou. 



216 RESPIRATION 



QUESTIONS FOR TOPICAL REVIEW 

PAGE 

1. What is the object of respiration ? 187 

2. What are the special organs of respiration ? 187 

3. In what organs does a change in the blood take place ? 187 

4. What is the nature of the change ? 187 

5. Where are the lungs situated, and what is the character of the sub- 

stance of which they are composed ? 187, 188 

6. Describe the facilities provided for the lung movements 188 

7. Describe the trachea, or windpipe 188-191 

8. Describe the bronchial tubes, and their uses 189 

9. What can you state in relation to the epiglottis ? 190 

10. What are the cilia, and what use do they probably serve ? 191 

11. How may the lungs be affected by not being properly protected ? . . 192 

12. Describe the movements necessary to the act of perfect respiration . 192, 193 

13. What is the diaphragm, and what is its office ? 192 

14. How may the organs of respiration be so improved as to increase 

their capacity and power ? 192 

15. What is stated in relation to the frequency of respiration ? 193 

16. To what extent may the act of respiration be subjected to oar wills ?. 194 

17. What may be said to be the capacity of the lungs ? 194 

18. How long does it take every particle of air in the lungs to be expelled 

and new air to take its place ? 194 

19. What would be the consequences, if the entire capacity of the lungs 

were constantly used ? 194, 195 

20. What would be the consequences to a fish put into water from which 

the air had been completely exhausted ? Why ? 195 

21. What is the air, and what are its parts ? 195, 196 

22. What is the character of the air that has been just breathed? 196 

23. Why is it that such air is not fit for respiration ? 196-198 

24. What are the effects, as recorded in notable cases of confinement in 

places the air of which has been breathed " over and over " ? . . 197, 198 

25. AVhat can you state of changes in the blood from respiration ? 198 

26. What of the air as an article of food ? 198, 199 

27. What on the subject of interchange of gases in the lungs ? 199 

28. Explain the difference between arterial and venous blood 199, 200 

29. Explain, if you can, the cause of the difference 200 

30. State what you can in relation to blue blood 200 

31. In relation to the amount of labor exerted in respiration 200, 201 

32. In relation to the deleterious properties of different gases 201 

33. In relation to the dust that floats in the air 202 

34. What are the properties of carbonic acid gas ? 203, 204 

35. In what places is carbonic acid gas commonly found ? 204 

36. Describe the effects of carbonic acid gas 204 

37. AVhat are the general effects of breathing any impure atmos- 

phere ? * 204-206 

38. What are Nature's provisions for purifying the air ? 207-209 

39. What hints and directions are given on the subject of ventilation ?. 209, 210 

40. How does the temperature of the body compare with the medium in 

which it lives ? 212 

41. How is temperature of the body regulated and sustained ? 212. 213 

42. State what you can on the subject of spontaneous combustion 213 



CHAPTER IX 

THE NERVOUS SYSTEM 

Animal and Vegetative Functions — Sensation, Motion, and Volition — 
TM Structure of the Nervous System — The White and Gray Sub- 
stances — The Brain — Its Convolutions — The Cerebellum — The 
Spinal Cord and its System of Nerves — The Anterior and Posterior 
Boots — The Sympathetic System of Nerves — The Properties of Ner- 
vous Tissue — Excitability of Nervous Tissues — The Functions of the 
Spinal Nerves and Cord — The Direction of the Fibres of the Cord — 
„ . Beflex Activity, and its Uses — The Functions of the Medulla Oblon- 
t gata and the Cranial Ganglia — The Beflex Action of the Brain — 
Effects of Alcohol, Tobacco, Snuff, Narcotics, Opium, Chloral, Hash- 
eesh, Chloroform 

1. Animal Functions. — The vital processes which we have 
been considering in the three previous chapters — of digestion, 
circulation, and respiration — belong to the class of functions 
known as vegetative functions. That is, they are common to 
vegetables as well as animals ; for the plant, like the animal, 
can originate nothing, not even the smallest particle of matter ; 
and yet it grows, blossoms, and bears fruit, by reason of obtain- 
ing and digesting the nutriment which the air and soil provide. 
The plant has its circulatory fluid and channels, by which the 
nutriment is distributed to all its parts. It has, also, a curious 
apparatus in its foliage, by which it abstracts from the air 
those gaseous elements so necessary to its support; and thus it 
accomplishes vegetable respiration. These vegetative functions 
have their beginning and end within the organism oi' the plant; 
and their object is the preservation of the plant itself, as well 
as of the entire species. 



1. What processes are known as the vegetative functions? Why so called ! 

properties and functions does the plant possess ? Their object } 

217 



218 THE NERVOUS SYSTEM 

2. The animal, in addition to these vegetative functions, has 
another set of powers, by the use of which he becomes con- 
scious of a world external to himself, and brings himself into 
active relations with it. By means of the vegetative processes, 
his life and species are maintained ; while, by means of certain 
animal functions, he feels, acts, and thinks. These functions, 
among which are sensation, motion, and volition, not only dis- 
tinguish the animal from the plant, but, in proportion to their 
development, elevate one creature above another ; and it is by 
virtue of his pre-eminent endowment, in these respects, that 
man holds his position at the head of the animal creation. 

3. Among animals whose structure is very simple — the 
hydra, or fresh-water polyp, being an example — no special 
organs are empowered to perform separate functions, but every 
part is endowed alike ; so that, if the animal be cut into pieces, 
each portion has all the properties of the entire original ; and, 
if the circumstances be favorable, each of the pieces will soon 
become a complete hydra. As we approach man, in the scale 
of beings, we find that the organs multiply, and the functions 
become more complete. The function of motion, the instru- 
ments of which — the muscles and bones — have been con- 
sidered in former chapters, and all the other animal functions 
of man, depend upon the set of organs known as the nervous 
system. 

4. The Nervous System. — The intimate structure of this 
system differs from any tissue which we have before examined. 
It is composed of a soft, pulpy substance, which early in life is 
almost fluid, but which gradually solidifies with the growth of 
the body. When examined under the microscope, it is found 
to be composed of two distinct elements : (1) the white sub- 
stance, composing the larger proportion of the nervous organs 
of the body, which is formed of delicate cylindrical filaments, 



2. What second set of powers has the animal ? What functions are mentioned ? The 
advantage they give ? 

3. Animals whose structure is simple ? As we approach man ? Dependence of the 
animal functions of man ? 

4. The nervous tissues, of what composed ? When examined by the aid of the micro- 
scope ? The white substance ? The gray substance ? 



THE NERVOUS SYSTEM 219 

about -g^Vo" of an i ncn i* 1 diameter, termed the nerve-fibres ; 
and (2) the gray substance, composed of grayish-red, or ashen- 
colored cells, of various sizes, generally possessing one or more 
off -shoots, which are continuous with the nerve-fibres just men- 
tioned. 

5. Each nerve-fibre is continuous from the nerve-centre from 
which it springs to that part of the body in which it ends. 
It consists of a white sheath and a gray axis cylinder within. 
The axis cylinder serves to convey the nerve-impulse, while 
the white sheath seems to serve as a protection, very similar 
to the insulation on electric wires. Many nerve-fibres unite 
into a bundle and form nerves. These nerve-bundles may be 
compared to electric cables containing many separate wires. 
The function of nerve-fibres is to convey nerve-impulses from 
the organs and periphery of the body to the nerve-centres, or 
from the nerve-centres to the organs and the periphery. 

6. The gray, cellular substance constitutes the larger por- 
tion of those important masses which bear the name of nervous 
centres and ganglia (from ganglion, a knot), in which all the 
nerve-fibres unite. The function of nerve-centres is three- 
fold: to receive nerve-impulses; to originate and impart 
nerve-impulses ; and to transmit nerve-impulses from one 
centre to another. That part of the nervous system which 
is concerned in the animal functions comprises the brain, the 
spinal cord, and the nerves which are derived therefrom; 
these are, together, called the cerebrospinal system (Fig. 54) ; 
while that other set of organs, which presides over and regu- 
lates the vegetative functions, is called the sympathetic system 
of nerves. 

7. The Brain. — The brain is the great volume of nervous 
tissue that is lodged within the skull. It is the largest and 
most complex of the nervous centres; its weight, in the adult, 

5. Of what does a nerve-fibre consist? Purpose of the axis cylinder? Of the white 
sheath ? What is the function of nerve-fibres ? 

6. Nervous centres and ganglia? Nerves? What do they serve? Cerebrospinal 
system? 

7. Location of the brain ? Its weight? Its shape? Of what does it consist ? What 
orgaus at the base ? 



220 THE NERVOUS SYSTEM 




Fig. 54. — The Cerebro-Spinal System 



THE NERVOUS SYSTEM 221 

being about fifty ounces, or one-fourth of that of the whole 
body. The shape of the brain is oval, or egg-shaped, with one 
extremity larger than the other, which is placed posteriorly in 
the skull, to the concavity of which it very closely conforms. 
The brain consists chiefly of two parts ; the cerebrum, or brain 
proper, and the cerebellum, or "little brain." In addition to 
these, there are several smaller organs at the base, among 
which is the commencement or expansion of the spinal cord, 
termed the medulla oblongata, or oblong marrow. 

8. The tissue of the brain is soft and easily altered in shape 
by pressure;, it therefore requires to be placed in a well-pro- 
tected position, such as is afforded by the skull, or cranium, 
which is strong without being cumbrous. In the course of 
an ordinary lifetime, this bony box sustains many blows with 
little inconvenience '; while, if they fell directly upon the brain, 
they would at once, and completely, disorganize that structure. 
Within the skull, the brain is enveloped by certain membranes, 
which at once protect it from friction and furnish it with a 
supply of nutrient vessels; they are called the arachnoid, or 
" spider's web," the dura mater, and the pia mater, or the 
"tough" and "delicate coverings." These membranes also 
cover the spinal cord. 

9. The dura mater is the outer covering. It is very strong 
and tough, being composed of white fibrous and elastic tissue. 
Next comes the arachnoid, which consists of two layers of flat 
cells, one next the dura mater, and the other next the pia 
mater. Between these two layers is contained a small quan- 
tity of watery cerebrospinal fluid. This fluid is also found on 
the pia mater in the folds of the brain surface. The pia mater 
adheres closely to the surface of the brain and spinal cord. It 
is less tough and less closely woven with fibrous and elastic 
tissue than the dura mater. It contains a network oi' blood- 
vessels which nourish the brain. The supply o( blood sent to 
the brain is very liberal, amounting to one-fifth of all thai the 

s. The tissue of the brain ? What, therefore, is required : ; Blows on the head I Mem- 
branes of the brain * Blood sent to the brain i 

9. The dura mater ? Arachnoid? Cerebrospinal fluid ? The pia mater ? 



222 



THE NERVOUS SYSTEM 



entire body possesses. The brain of man is heavier than that 
of any other animal, except the elephant and whale. 

10. The Cerebrum. — The brain proper, or cerebrum, is the 
largest of the intracranial organs, and occupies the entire upper 
and front portion of the skull. It is almost completely bisected 
by a fissure, or cleft, running through it lengthwise, into two 
equal parts called hemispheres. The exterior of these hemi- 




Fig. 55. — Upper Surface of the Cerebritm 
A, Longitudinal Fissure B, The Hemispheres 

spheres is gray in color, consisting chiefly of nerve-cells, arranged 
so as to form a layer of gray matter one-fifth of an inch in 
thickness, and is abundantly supplied with blood-vessels. The 
interior of the brain, however, is composed almost wholly of 
white substance, or nerve-fibres. 

11. The surface of the cerebrum is divided by a considerable 
number of winding and irregular furrows, about an inch deep, 



10. Where is the cerebrum located ? How is it divided 
hemispheres. The interior. 



Describe the exterior of the 



THE NERVOUS SYSTEM 223 

into " convolutions," as shown in Fig. 55. Into these furrows 
the gray matter of the surface is extended, and, in this manner, 
its quantity is vastly increased. The extent of the entire sur- 
face of the brain, with the convolutions unfolded, is computed to # 
be equal to four square feet ; .and yet it is easily enclosed within 
the narrow limits of the skull. When it is stated that the 
gray matter is the true source of nervous power, it becomes 
evident that this arrangement has an important bearing on the 
mental capacity of the individual. And it is noticed that in 
children, before the mind is brought into vigorous use, these 




Fig. 56. — Vertical Section of the Brain 

A, Left Hemisphere of Cerebrum D, The Pons Varolii 

B, Corpus Callosum E, Upper extremity of the Spinal Cord 
0, Optic Thalamus F, The Arbor Vita> 



markings or furrows on the surface are comparatively shallow 
and indistinct; the same fact is true of the brain in the loss 
civilized races of mankind and in the lower animals. It is also 
noticeable that among animals, those are the most capable 

11. The surface of the cerebrum, bow marked ? The jrray matter of the surface J Ex- 
tent of the entire brain surface ? Source of nervous power * What farther J 



224 



THE NERVOUS SYSTEM 



of being educated which have the best development of the 
cerebrum. (Bead Note 1.) 

12. The Cerebellum. — The "little brain" is placed beneath 
the posterior part of the cerebrum, and, like the latter, is 




Fig. 57. — Lowek Surface of the Brain 
The numbers refer to the pairs of nerves 

divided into hemispheres. Like it, also, the surface of the 
cerebellum is composed of gray matter, and its interior is 

1. The Brain. — " Our brains are seventy-year clocks. The Angel of 
Life winds them up once for all, then closes the case, and gives the key 
to the Angel of the Resurrection. Tic-tac ! tic-tac ! go the wheels of 
thought ; our will cannot stop them ; they cannot stop themselves ; sleep 
cannot stop them ; madness only makes them go faster ; death alone can 
break into the case, and, seizing the ever-swinging pendulum, which we 
call the heart, silence at last the clicking of the terrible escapement we 
have carried so long beneath our wrinkled foreheads. . . . Now, when 
a gentleman's brain is ill-regulated or empty, it is, to a great extent, his 
own fault, and so it is simple retribution that, while he lies slothfully or 
aimlessly dreaming, the fatal habit settles on him like a vampire and 
sucks his blood, fanning him all the while with its hot wings into deeper 
slumber or idler dreams." — Holmes' The Autocrat of the Breakfast- Table. 



12. Location of the "little brain 
divisions ? Its size ? 



How divided ? Its surface and interior ? Its sub- 



THE NERVOUS SYSTEM 225 

chiefly white matter. It has, however, no convolutions, but is 
subdivided by many parallel ridges, which, sending down gray 
matter deeply into the white, central portion, give the latter 
a somewhat branched appearance. This peculiar appearance 
has been called the arbor vitm, or the " tree of life," from the 
fact that when a section of the organ is made, it bears some 
resemblance to the trunk and branches of a tree (Fig. 56, F). 
In size, this cerebellum, or " little brain," is less than one- 
eighth of the cerebrum. 

13. From the under surface of the cerebrum, and from the 
front margin of the cerebellum, fibres collect together to form 
the medulla oblongata (Fig. 57, Ma), which, on issuing from 
the skull, enters the spinal column, and then becomes known 
as the spinal chord. From the base of the brain, and from the 
sides of the medulla originate, also, the cranial nerves, of which 
there are twelve pairs. These nerves are round cords of 
glistening white appearance, and, like the arteries, generally 
lie remote from the surface of the body, and are well protected 
from injury. 

14. The Cranial Nerves 

First Pair. The Olfactory Nerves 

They pass from the base of the brain to the horizontal plate 
of the ethmoid bone, and send numerous filaments through its 
many perforations into the mucous membranes of the nose. 
They convey the sense of smell. 

Second Pair. The Optic Nerves 

They convey the sense of sight, and control the contractile 
movements of the iris. 

Third Pair. The Oculomotorius 
It supplies most of the muscles moving the eyeball. 



ltf. Of what is the medulla oblongata formed f 
Of what does it form ;i part } 
Source of the cranial nerves ? How many J 
Appearance of the cranial nerves ? Location J 



226 THE NERVOUS SYSTEM 

Fourth Pair. The Patheticus 

Its only function is to control the action of the superior 
oblique muscle of the eye. 

Fifth Pair. Tlie Trigeminus 

This is the great sensitive nerve of the face, supplying the 
skin and mucous membrane of this region. It also has motor 
fibres which control certain muscles of the face. It also sup- 
plies certain parts of the eye, nose, and lachrymal glands, the 
teeth in both the upper and lower jaws, the salivary glands, 
and the tongue. 

Sixth Pair. The Abducens 

It is exclusively a motor nerve, controlling only one muscle, 
namely, the external straight muscle of the eyeball. 

Seventh Pair. Tlie Facial Nerves 

They are the motor nerves for the superficial muscles of the 
face, and may be correctly called the nerves of expression, by 
which the features are animated in their varying movements, 
corresponding with the different phases of mental or emotional 
activity. 

Eighth Pair. Tlie Auditory Nerves 

They are distributed to the internal ear only, and form the 
only connection between this and the brain, transmitting the 
nerve impulses which produce the sensation of sound. 

Ninth Pair. The Glossopharyngeal Nerves 

They are both sensitive and motor nerves, controlling the 
sense of taste and the act of deglutition. 

14. What is stated of the olfactory nerves ? The optic nerves ? 
The oculomotorius ? The patheticus ? The trigeminus ? 
The abducens ? The facial nerves ? The auditory nerves ? 
The glossopharyngeal ? 



THE NERVOUS SYSTEM 227 

Tenth Pair. Tlie Pneumogastric Nerves 

They are the longest and most widely distributed of all the 
cranial nerves. It goes to the pharynx, oesophagus, stomach, 
liver, intestines ; to the larynx, trachea, lungs, and heart. 

Eleventh Pair. Tlie Spinal Accessory Nerves 

As its name implies, this nerve received a part of its origin 
from the spinal cord, in the cervical region. A portion of it 
is incorporated in the vagus, and the other part supplies cer- 
tain muscles of the neck and chest. Some of its fibres entirely 
control the power of the vocal chords to produce sounds. 

Twelfth Pair. The Hypoglossal Nerves 
Its only function is the control of the motions of the tongue. 

15. The Spinal Cord. — The spinal cord, or "marrow," is a 
cylindrical mass of soft nervous tissue, which occupies a 
chamber, or tunnel, fashioned for it in the spinal column 
(Figs. 58 and 59). It is composed of the same substances 
as the brain; but the arrangement is exactly reversed — the 
white matter encompassing or surrounding the gray matter, 
instead of being encompassed by it. The amount of the white 
substance is also greatly in excess of the other material. A 
vertical fissure partly separates the cord into two lateral halves, 
and each half is composed of two separate bundles of fibres, 
which are named the anterior and posterior columns. 

16. These columns have entirely different uses, and each of 
them unites with a different portion of the nerves which have 
their origin in the spinal cord. The importance of this part 
of the nervous system is apparent from the extreme care taken 

What is stated of the pneumogastric nerves ? The spinal accessory nerves ? The 
hypoglossal nerves ? 

15. Describe the composition of the spinal cord. What space does the spinal cord oc- 
cupy? I u what respect does the substance composing the spinal cord and the substance 
composing- the brain agree ? In what respect do they differ? Does white or gray matter 
predominate in the spinal cord ? In the brain ? How is the spinal cord divided ? Compo- 
sition of each half? Names ? 

16. Uses of these columns? Importance of this part of the nervous system? How- 
protected ? The three membranes that cover the brain ? 



228 



THE XERVOUS SYSTEM 



to protect it from external injury. For, while a very slight 
disturbance of its structure suffices to disarm it of its power, 
yet so staunch is its bony enclos- 
ure, that only by very severe inju- 
ries is it put in peril. The three 
membranes that cover the brain are 
continued downward, so as to en- 
velope and still further shield this 
delicate organism. 

17. The Spinal Nerves. — The 
spinal nerves, thirty-one pairs in 
number, spring from each side of 
the cord by two roots, an anterior 
and a posterior root, which have the 
same functions as the columns bear- 
ing similar names. The posterior 
root is distinguished by possessing 
a ganglion of gray matter, and by a 
somewhat larger size. The succes- 
sive XDoints of departure, or the off- 
shooting of these nerves, occur at 
short and nearly regular intervals 
along the course of the spinal cord. 
Soon after leaving these points, the 
anterior and posterior roots unite to 
form the trunk of a nerve, which is 
distributed, by means of branches, 
to the various organs of that part 
of the body which this nerve is 
designed to serve. The spinal 
nerves supply chiefly the muscles 
of the trunk and limbs and the 
external surface of the body. 

18. The tissue composing the FlGl 58 

,. i P ,, -, . . A, Cerebrum, B. Cerebellum, 

nerves is entirely ot the white Di D spinal Cord 




17. The spinal nerves ? The posterior root ? The nerves, how arranged ? Their office ? 

18. The nerve tissue ? Its character ? Course of each nerve-fibre ? 



THE NERVOUS SYSTEM 



229 



variety, or, in other words, the nerve-fibres ; the same as we 
have observed forming a part of the brain. But the nerves, 
instead of being soft and pulpy, as in the case of the brain, 
are dense in structure, being hardened and strengthened by 
means of a fibrous tissue which surrounds each of these deli- 
cate fibres, and binds them together in glistening, silvery 
bundles. Delicate and minutely fine as are these nerve-fibres, 




Fig. 59. — Section of Spinal Cord, with Eoots of Spinal Nerves. Front View 

it is probable that each of them pursues an unbroken, isolated 
course, from its origin, in the brain or elsewhere, to that par- 
ticular point which it is intended to serve. For, although their 
extremities are often only a hair's breadth distant from each 
other, the impression which any one of them communicates is 
perfectly distinct, and is referred to the exact point whence 
it came. 

19. This may be illustrated in a simple manner, thus : if two 
fingers be pressed closely together, and the point of a pin be 
carried lightly across from one to the other, the eyes may be 
closed, and yet we can easily note the precise instant when 
the pin passes from one finger to the other. If , the nerve- 
fibres were less independent, and if it were necessary that they 
should blend with and support each other, all accuracy of 
perception would be lost, and all information thus afforded 
would be pointless and confused. These silvery threads must. 
therefore, be spun out with an infinite degree of nicety. Imag- 
ine, for instance, the fibre which connects the brain with some 



19. How may wo illustrate the tact I The fibre connecting the brain with a point in the 
foot? 



230 THE NERVOUS SYSTEM 

point on the foot — its length cannot be less than one hundred 
thousand times greater than its diameter, and yet it performs 
its work with as much precision as fibres that are compara- 
tively much stronger, and less exposed. (Bead Note 2.) 

20. The Sympathetic System. — The sympathetic system of 
nerves remains to be described. It consists of a double chain 
of ganglia, situated on each side of the spinal column, and 
extending through the cavities of the trunk, and along the 
neck into the head. These ganglia are made up for the most 
part of small collections of gray nerve-cells, and are the nerve- 
centres of this system. From these, numerous small nerves 
are derived, which connect the ganglia together, send out 
branches to the cranial and spinal nerves, and form networks 
in the vicinity of the stomach and other large organs. A con- 
siderable portion of them also follows the distribution of the 
large and small blood-vessels, in which the muscular tunic 
appears. Branches also ascend into the head, and supply the 
muscles of the eye and ear, and other organs of sense. 

2. How Bodily Sensations are Located. — "A nervous fibre which ends 
in the skin forms, as far as its union with the brain or cord is concerned, 
one long, fine, unbroken thread. The fibres, thus ending in the skin, 
very soon join to form small branches, and finally in thick nerve trunks, 
but in no case do two nerve fibres coalesce so as to lose their identity. 
Every part of the skin has its own separate connections with the centre 
of the nervous systems, which unite there just as telegraph wires unite 
at a terminus. The brain is the terminus of these lines of nerves, and, 
as it were, receives and explains the messages sent to it. It distinguishes 
very clearly by what particular fibre such a message has come, and just 
as the clerk in a telegraph office, where a great many wires meet from all 
sides, knows by experience from what direction each wire brings its 
message, so the brain also knows by experience what part of the skin 
is involved when a sensation reaches it along a certain nerve fibre. It is 
probable that the brain, by its imaginative faculty, has formed a complete 
picture of the surface of the body — a kind of chart slowly made, and 
always being more highly perfected, by means of which, with each im- 
pression from without, there arises in the brain a picture of the spot upon 
the skin where the irritation has taken place. Now, if an irritation were 
to pass from one nerve fibre to another, it is very plain, the brain could 
not tell the place from which it came, and could not localize impressions 
received from the world about us." — Bernstein's Five Senses of Man. 



20. The sympathetic system of nerves ? Of what does it consist ? 



THE NERVOUS SYSTEM 231 

21. In this manner, the various regions of the body are 
associated with each other by a nervous apparatus, which is 
only indirectly connected with the brain and spinal cord, and 
thus it is arranged that the most widely separated organs of 
the body are brought into close and active sympathy with each 
other, so that " if one member suffers, all the other members 
suffer with it." From this fact, the name sympathetic system, 
or the great sympathetic nerve, has been given to the compli- 
cated apparatus we have briefly described. Blushing and 
pallor are caused by mental emotions, as modesty and fear, 
which produce opposite conditions of the capillaries of the 
face by means of these sympathetic nerves. ( Bead Note 3.) 

22. The Properties of Nervous Tissue. — We have seen that 
in all parts of this system there are only two forms of nervous 
tissue, namely, the gray substance and the white substance, so 
called from their difference of color as seen by the naked eye ; 

3. The Wonderful Operations of the Sympathetic System. — Blush- 
ing or " Shame-redness." — " A blow upon the head will knock a man 
senseless, but he still lives and survives ; a blow of like violence upon 
the pit of the stomach is followed by instant death, because the great 
centre of the organic nerves lies there, and the vital actions are suspended 
by the blow, so that the system never lives to recover, but abolition of 
function and of life at once follows. Other actions also belong to this 
organic nervous system. It controls the caliber of the blood-vessels, for 
which end filaments run along each of them. The body temperature is 
maintained by the production and dispersion of heat thus regulated, a 
continuous oscillation going on betwixt the internal vessels and those of 
the skin. It is connected with the emotions ; and so the heart beats per- 
ceptibly with excitement, and the maiden's cheek blushes before words 
that should never be spoken, or thoughts that should never arise. The 
momentary dilatation of the vessels of the skin constitutes the blush (in 
the German, 'shame-redness'), which is not confined to the face, though 
of course it is only seen there — the body being hid by the clothes." — 
Fothergill on the Maintenance of Health. 

" There is an old tradition that when the executioner of Charlotte 
Corday lifted her severed head high in air, and smote the face with his hand, 
the cheeks were seen to resent the insult with a blush. This reddening is 
not impossible, for a decapitated head certainly may exhibit, for a time, 
certain reflex movements. But whether sensibility is retained cannot be 
known." 



21. Association of the various regions of the body ? If one member sutlers ? Rhishinc ? 

22. Properties of nervous tissue ? Office of the gray substance ? Of the white ? The 
nervous centres ? White fibres ? 



232 THE NERVOUS SYSTEM 

or the nerve-cell, and the nerve-fibre, so called from their 
microscopic appearance. Now these two tissues are not com- 
monly mingled together, but either form separate organs or 
distinct parts of the same organs. This leads us to the con- 
clusion that their respective uses are distinct. And this proves 
to be the simple fact ; wherever we find the gray substance, we 
must look upon it as performing an active part in the system 
— that is, it originates nervous impulses ; the white matter, on 
the contrary, is a passive agent, and serves merely as a con- 
ductor of nervous influences. Accordingly, the nervous centres, 
composed so largely of the gray cells, are the great centres of 
power, and the white fibres are simply the instruments by 
which the former communicate with the near and distant 
regions of the body under their control. 

23. We may compare the brain, then, to the capital, or seat 
of government, while the various ganglia, including the gray 
matter of the cord, like so many subordinate official posts, are 
invested with authority over the outlying provinces ; and the 
nerves, with the white matter of the cord, are the highways 
over which messages go and return between these provinces 
and the local or central governments. But both forms of ner- 
vous tissue possess the same vital property called excitability, 
by which term is meant that, when a nerve-cell or fibre is 
stimulated by some external agent, it is capable of receiving 
an impression, and of being by it excited into activity. A ray 
of light, for example, falling upon one extremity of a fibre in 
the eye, excites it throughout its whole length ; and its other 
extremity within the brain, communicating with a nerve-cell, 
the latter in its turn is excited, and the sensation of sight is 
produced. (Bead Note 4.) 

4. The Relations of the Brain and Sympathetic Nerve. — " Buried in 
the hidden recesses of the body, between the spinal column and the great 
organs of nutrition, there is a double row of small knots of nervous sub- 
stance, bound together by a series of nerves running from one to another, 
in succession, from the neck to the base of the column. The whole 
appears like a long, fine cord, with knots at various distances — a collec- 



23. What comparison is made between the brain and the nation's capital ? The vital 
property, excitability ? What example is given ? 



THE NERVOUS SYSTEM 233 

24. What sort of change takes place in the nervous tissue 
when its excitability is aroused, is not known ; certainly none 
is visible. On this account, it has been thought by some that 
the nerve-fibre acts after the manner of a telegraph wire ; that 
is, it transmits its messages without undergoing any material 
change of form. But though the comparison is a convenient 
one, it is far from being strictly applicable, and the notion 
that nerve-force is identical with electricity has been fully 
proved to be incorrect. 

25. The Functions of the Nerves. — The nerves are the in- 
struments of the two grand functions of the nervous system — 
Sensation and Motion. They are not the true centres of either 
function, but they are the conductors of influences which occa- 
sion both. If the nerve in a limb of a living animal be laid 
bare, and irritated by pinching, galvanizing, or the like, two 
results follow, namely: the animal experiences a sensation, 
that of pain, in the part in which the nerve is distributed, and 
the limb is thrown into convulsive action. When a nerve in a 
human body is cut by accident, or destroyed by disease, the 
part in which it ramifies loses both sensation and power of 
motion; or, in other words, it is paralyzed. We accordingly 
say that the nerves have a two-fold use — a sensory and a 
motor function. 

tion of little brains, if I may use a rather crude expression. It is, as the 
Swiss would say, the 'great council' of this federative republic, which 
counterpoises that cerebral royalty within us. It has been well named 
the great sympathetic nerve, and this it is which makes the laws by 
which our interior life is governed. The nutritive apparatus of a country, 
its commerce, its industry, the incessant labor of its citizens, by which 
the public wealth is built up — and also let us add, the throbs of the 
national heart — all this the sympathetic system full plainly shows us 
should be left to itself. It would be a fine affair if the brain had to 
watch over the service of the stomach, or if, at its convenience, it regu- 
lated the movements of the master who disposes of its life. Besides, 
what would become of the poor body if the least drowsiness attacked the 
universal centre ? Happy it is for us — and let us not be slow to own it — 
that nature has armed herself against these encroachments of power." — 
Mace's The Little Kingdom. 



24. Change in the nervous tissues •> Nerve force and electricity \ 

25. Functions of the nerves,? In the case of the nerve of a living 

huuiau body ? 



234 



THE NERVOUS SYSTEM 




Fig. 60. 



Illustrating the Functions of the 
Spinal Nerves 



Divided at a. — Irritated at 1 : pain, 
muscular contraction 



Irritated at ! 



26. If a nerve that has been exposed be divided, and the 
inner end, or that still in connection with the nerve-centres be 
irritated, sensation is produced, but no movement takes place. 
But if the outer end, 
or that still connected 
with the limb, be irri- 
tated, then no pain is 
felt, but muscular con- 
tractions are produced. 
Thus we prove that 
there are two distinct 
sets of fibres in the 
nerves — one of which, 
the sensory fibres, conduct toward the brain, and another, the 
motor fibres, conduct to the muscles (see Fig. 60). The 
former may be said to begin in the skin and other organs 
and end in the brain, while the latter begin in the nervous 
centres and end in the muscles. They are like a double line 
of telegraph wires, one for inquiries, the other for responses. 

27. We have already spoken of the two roots of the spinal 
nerves, called, from their points of origin in the spinal cord, 
the anterior and posterior roots. These have been separately 
cut and irritated in the living animal, and it has been found 
that the posterior root contains only sensory fibres, and the 
anterior root has only motor fibres. So that the nerves of a 
limb may be injured in such a way that it will retain power of 
motion and yet lose sensation ; or the reverse condition, feeling 
without motion, may exist. Between these two sorts of fibres 
no difference of structure can be found ; and where they have 
joined to form a nerve, it is impossible to distinguish one sort 
from the other. 

28. Occasionally a nerve is so compressed as to be tempo- 
rarily unable to perform its functions : a transient paralysis 



26. If an exposed nerve be divided ? What is proved ? The course of the sensory set 
of fibres ? Of the motor set ? To what are they likened ? 

27. The two roots of the spinal nerves ? What has been found ? Difference of the two 
sorts of fibres ? Result of their union ? 

2S. Transient paralysis ? When such is the case with the leg ? What other fact ia 
observed ? 



THE NERVOUS SYSTEM 235 

then takes place. This is the case when the leg or arm " gets 
asleep," as it is expressed. When such is the condition with 
the leg, and the person suddenly attempts to walk, he is liable 
to fall, inasmuch as the motor fibres cannot convey orders to 
the muscles of the limb. Another fact is observed: there is 
no sensation in this nerve at the point of its compression ; but 
the whole limb is numb, and tingling sensations are felt in the 
foot — the point from which the sensory fibres arise. 

29. This illustrates the manner in which the brain inter- 
prets all injuries of the trunk of a nerve. Sensation or pain 
is not felt at the point of injury, but is referred to the outer 
extremities of the nerve, where impressions are habitually 
received. This is the reason why, after a limb has been 
amputated by the surgeon, the patient appears to suffer pain 
in the member that has been severed from the body; while 
some form of irritation at the end of the nerve in the wound, 
or stump, is the real source of his distress. Again, when the 
" funny-bone" — that is, the ulnar nerve at the elbow — is 
accidentally struck, the tingling sensations thus produced are 
referred to the outer side of the hand and the little finger, the 
parts to which that nerve is distributed. 

30. All the spinal nerves, and two from the brain, are con- 
cerned in both sensation and motion. Of the remainder of 
the cranial nerves, some are exclusively motor, others exclu- 
sively sensory; and still others convey, not ordinary sensa- 
tions, but special impressions, such as sight, hearing, and 
smell, which we have yet to consider. However much the 
functions of the nerves seem to vary, there is but little dif- 
ference discoverable in the nerves themselves, when examined 
under the microscope. Whatever difference exists must be 
accounted for in consequence of the nerves communicating 
with different portions of the gray matter of the brain. The 
rate of motion of a message, to or from the brain along a 



29. What does this illustrate ? Sensation? The feeling after a limb has been ampu- 
tated ? Striking of the " funny-bone ? " 

80. The spinal nerves, and two from the brain ? Of the remainder ? Difference m the 
nerves? How accounted lor ? The rate of conduction along a nerve ? As com pared with 
electricity ? 



236 THE NERVOUS SYSTEM 

nerve, has been measured by experiment upon the lower ani- 
mals, and estimated in the case of man at about two hundred 
feet per second. As compared with that of electricity, this is 
a very slow rate, but, in respect to the size of the human 
body, it is practically instantaneous. (Bead Xote 5.) 

31. The Functions of the Spinal Cord. — As the anterior and 
posterior roots of the spinal nerves have separate functions, so 
the anterior and posterior columns of the cord are distinct 
in function. The former are concerned in the . production of 
motion, the latter in sensation. If the cord be divided, as 
before in the case of the nerve, it is found that the parts 
below the point of injury are deprived of sensation and of 
the power of voluntary motion on both sides of the body — a 
form of paralysis which is called paraplegia. 

32. This form of disease — paraplegia — is sometimes seen 
among men, generally as the result of a fall, or some other 
severe accident, by which the bones of the spine are broken, 
and the cord is crushed, or pierced by fragments of bone. 
The parts which are supplied by nerves from the cord above 
the point of injury are as sensitive and mobile as before. The 
results are similar, whether the division happens at a higher 
or lower portion of the spinal cord; but the danger to 
life increases proportionately as the injury approaches the 
brain. When it occurs in the neck, the muscles of inspira- 



5. The Speed of Sensation and Thought. — -'The rate of nervous 
and mental action is not the same in all individuals. In comparing the 
records made by astronomers, it has been found that an appreciable dif- 
ference exists in the rapidity with which the same occurrence may be 
noted by different observers. This is known as the 'personal equation,' 
and is allowed for with the greatest nicety in the making up of astro- 
nomical reports. With very delicate apparatus for marking time, the 
various nervous impulses have been observed; from forty to a hun- 
dred feet in a second are the estimates of different experiments as to the 
speed of sensation ; or, as it has been expressed, it would take a full- 
grown whale a second to feel the stroke of a harpoon in his tail." 



31. Functions of the anterior and posterior, columns of the cord ? If the cord be 
divided ? 

32. Paraplegia ? Eesult and danger to life ? When the injury occurs in the neck ? 



THE NERVOUS SYSTEM 237 

tion are paralyzed, since they are supplied by nerves issu- 
ing from that region; and as a result of this paralysis, 
the lungs are unable to act, and life is speedily brought to 
a close. 

33. When the spinal cord of an animal has been cut, in 
experiment, it may be irritated in a manner similar to that 
alluded to when considering the nerves. If, then, the upper cut 
surface be excited, it is found that pain, referable to the parts 
below the cut, is produced ; but when the lower cut surface is 
irritated, no feeling is manifested. So we conclude that in 
respect to sensation, the spinal cord is not its true centre, but 
that it is merely a conductor, and is therefore the great sensory 
nerve of the body. When the lower surface of the cut is irri- 
tated, the muscles of the parts below the section are violently 
contracted. Hence we conclude that, in respect to the move- 
ments ordered by the will, the spinal cord is not their source, 
but that it acts only as a conductor, and is, accordingly, the 
great motor nerve of the body. 

34. Direction of the Fibres of the Cord. — If one lateral half 
of the spinal cord be cut, or injured, a very singular fact is 
observed. All voluntary power over the muscles of the corre- 
sponding half of the body is lost, but the sensibility of that 
side remains undiminished. This result shows that the motor 
fibres of the cord pursue a direct course, while its sensory 
fibres are bent from their course. And this has been proved to 
be the fact; for immediately after the posterior roots — the 
conductors of sensory impressions — join the posterior columns, 
they enter the gray matter of the cord, and passing over, 
ascend to the brain on the opposite side. Accordingly, the 
sensory fibres from the right and left sides interlace each other 
in the gray matter; this arrangement has been termed the 
decussation, or crossing of these fibres. This condition serves 
to explain how a disease or injury of the cord may cause a 
paralysis of motion in one leg, and a, loss of sensation in the 
other. 



83. Experiment Of cutting the spinal cord of an animal ? What inference is drawn 1 

84, What, singular fact is notioed ? What docs the result sho* I 



238 THE NERVOUS SYSTEM 

35. The direction of the anterior, or motor columns of the 
cord, is downward from the brain. In the cord itself, the 
course of the motor fibres is for the most part a direct one ; 
but in the medulla oblongata, or upper extremity of the cord, 
and therefore early in their career, these fibres cross from side 
to side in a mass, and not separately, as in the case of the 
posterior fibres just mentioned. This arrangement is termed 
the decussation of the anterior columns of the medulla. 

36. From this double interlacing of fibres results a cross 
action between the original and terminal extremity of all 
nerve-fibres which pass through the medulla — namely, those 
of all the spinal nerves. Consequently, if the right hand be 
hurt, the left side of the brain feels the pain ; and if the left 
foot move, it is the right hemisphere which dictates its move- 
ment. For the same reason, when a loss of sensation and 
power of motion affecting the right side of the body alone is 
observed, the physiologist understands that the brain has been 
invaded by disease upon its left side. This affection is termed 
hemiplegia, or the "half -stroke." The full-stroke, which often 
follows the rupture of a blood-vessel in the brain, is commonly 
called paralysis. 

37. The Reflex Action of the Cord. — We have already con- 
sidered the cord as the great motor and sensory nerve of the 
body, but it has another and extremely important use. By 
virtue of the gray matter, which occupies its central portion, it 
plays the part of an independent nerve centre. The spinal 
cord not only conducts some impressions to the brain, but it 
also arrests others ; and, as it is expressed, " reflects " them 
into movements by its own power. This mode of nervous 
activity is denominated the reflex action of the cord. 

38. A familiar example of this power of the cord is found in 
the violent movements which agitate a fowl after its head has 

35. Direction of the anterior or motor columns? In the cord itself? In the medulla 
oblongata ? The decussation ? 

86. Result of the double interlacing of fibres ? Where is the seat of pain when the right 
hand is hurt ? The moving of the foot ? Loss of sensation in one side of the body ? 

37. What other important use has the cord ? What is the activity denominated ? 

3S. Example of the fowl ? Centipede ? Frog ? What do they prove ? 



THE NERVOUS SYSTEM 239 

been cut off. The cold-blooded animals also exhibit reflex 
movements in an astonishing degree. A decapitated centipede 
will run rapidly forward, and will seemingly strive to over- 
turn, or else climb over obstacles placed in its way. A frog 
similarly mutilated will sustain its headless body upon its feet, 
in the standing posture, just as it might do if it were still 
alive. If pushed over, it will regain its feet ; and if the feet 
are irritated, it will jump forward. There can be no doubt 
that, in the lower animals, movements may take place which 
are completely divorced from the will, sensation and conscious- 
ness ; for in those animals, as well as in man, these faculties 
have their principal seat within the brain. 

39. An irritation is necessary, in most instances, to awaken 
reflex movements. In the case of the decapitated fowl, its 
muscles are excited to convulsive action by reason of its being 
thrown upon the hard ground and roughly handled. Let it be 
treated differently, and the convulsions will not take place : 
let it be laid gently upon soft cotton, and the body will remain 
comparatively quiet. It may comfort some people to know 
that the convulsions which follow decapitation are not attended 
with pain, nor are they a necessary part of the " act of death," 
as some suppose. 

40. In the human body, likewise, actions are excited that 
are entirely distinct from the ordinary voluntary efforts. It is 
not permissible, desirable, nor even necessary to decapitate a 
man that the body may be disconnected from his brain, in 
order to test the effect of irritation upon the spinal cord — 
although the bodies of beheaded criminals have been experi- 
mented upon, and caused to move by powerful galvanic bat- 
teries. Such experiments are rendered unnecessary by the 
occurrence of certain deplorable cases of disease and injury, 
which effectually sever all communication between the brain 
and a large part of the body. 

41. Thus, the cord by an accident may be so far injured as 



89. What is necessary in most cases to awaken rellex movements ? In the case of the 

fowl ? Convulsions which follow decapitation ? 

40. Actions in the human body distinct from voluntary efforts J 

41. Keflex action after injury of the cord 1 Why not due to the muscles ? 



240 THE NERVOUS SYSTEM 

to terminate all sensation and voluntary motion in the lower 
half of the body, the patient seeming lifeless and powerless from 
the waist downward. And yet, by tickling or pinching either 
foot, the leg of the same side may be made to jerk, or even 
to kick with considerable force ; but, unless the patient is ob- 
serving his limbs, he is wholly unconscious of these movements, 
which are, therefore, performed independently of the brain. 
And they are in nowise due to the muscles of the limb ; for, 
if the cord itself become diseased below the point of injury, 
the muscles cease to contract. 

42. For the production of this form of nervous action, three 
things are requisite — (1) a nerve to conduct messages from 
the surface of the body, one of that variety formerly described 
as sensory, but which are now known to be incapable of awaken- 
ing sensation ; (2) a portion of uninjured spinal cord, which 
shall reflect or convert impressions into impulses; and (3) a 
motor nerve to conduct impulses outward to the muscles. The 
power of the cord to enforce reflex acts resides in the gray 
matter, into which the reflex nerves enter and from which 
they depart, by means of their posterior and anterior roots 
respectively. 

43. The Uses of the Reflex Action. — The reflex activity of 
the cord is exhibited in the healthy body in many ways, but 
since it is never accompanied with sensation, we do not readily 
recognize it in our own bodies. Reflex movements are best 
studied in the cases of other persons, when the conditions en- 
able us to distinguish between acts that are consciously, and 
those that are unconsciously performed. For example, if the 
foot of a person soundly asleep be tickled or pinched, it will 
be quickly withdrawn from the irritation. 

44. Similar movements may be observed in cases where the 
consciousness and sensation are temporarily obliterated by 
disease, or by means of narcotic poisons. If the arm of a per- 
son who has been rendered insensible by chloroform be raised, 



42. What are the requisites for the production of this form of nervous action ? 

43. Why do we not readily recognize the reflex activity of the cord in our own bodies ? 
How best studied in others ? Example ? 

44. Similar movements ? Arm of a person . Melted wax or heated coin on the hand ? 



THE NERVOUS SYSTEM 241 

and then allowed to fall, it will be noticed that the limb does 
not drop instantly, like a lifeless member, but a certain amount 
of rigidity remains in its muscles, which resists or breaks the 
force of its descent. Again, when a substance like melted 
sealing-wax, or a heated coin, falls upon the hand, the limb is 
snatched away at once, even before the feeling of pain has 
been recognized by the brain. When jolted in a rapidly mov- 
ing car, we involuntarily step forward or backward, so as to 
preserve the centre of gravity of the body. 

45. These and similar acts are executed by the same mechan- 
ism as that previously described in the case of paralysis from 
an injury of the spinal cord. The muscles thus called into 
play are those which are ordinarily under the sway of the will, 
but which in these cases act through this reflex action of the 
cord, altogether independently of the will. A healthful reflex 
activity produces an elasticity, or " tone," in the voluntary mus- 
cular system, which in a great measure explains the existence 
in the young and vigorous of a feeling of buoyancy and reserve 
power. Its possessor is restlessly active, and it may appropri- 
ately be said of him, "he rejoiceth as a strong man to run a 
race." But this reflex energy may be deficient. This is true 
when the blood is poor and wanting in its solid ingredients, or 
the circulation is feeble; the muscles, then, are flabby and 
weak, and the person himself is said to be " nerveless," or in- 
disposed to exertion. Shivering from cold and trembling from 
fear may, in part, be referred to a temporary loss of tone, 
resulting from a powerful impression upon the brain. (Bead 
Note 6.) 

6. On Nervous Health, or Tone. — " That state of general vigor, which 
we call ' tone,' depends upon the healthy action of the nervous centres. 
It consists in the habitual moderate contraction of the muscles, due to a 
constant stimulus exerted on them by the cord, and is valuable less for 
itself than as a sign of a sound nervous balance. Tone is maintained 
partly by healthful impressions radiated upon the spinal cord through the 
nerves from all parts of the body, and partly by the stimulus poured 
down upon it from the brain. So it is disturbed by whatever conveys 
irritating or depressing influences in either direction. A single injiuli- 



46. Result of healthful reflex activity ? Wheu mvy the reflex eucrg} be defleieuty 



242 THE NERVOUS SYSTEM 

46. An excess of this activity may also be observed in 
disease. In this condition, the excitability of the cord is 
unnaturally aroused, and frequent and violent movements of 
the limbs and body, called convulsions, are the result. The 
convulsions of young children, and the nervous agitation of 
chorea, or St. Vitus's dance, are reflex in character, as are also 
the symptoms attending poisoning by strychnine, and those 
terrible diseases, tetanus, or "locked jaw/' and hydrophobia. 
The severity of the convulsions is not the same in all cases of 
these disorders ; but, in those last mentioned, the most violent 
spasmodic movements are provoked by the slightest form of 
irritation — such as the sound of pouring water, the sight of 
any glittering object, the glancing of a mirror, the contact 
of cool air, or even the touch of the bed-clothes. 

47. Another variety of reflex motions takes place in certain 
involuntary muscles, and over these the cord exercises supreme 
control. They are principally those movements which aid the 
performance of digestion and nutrition, the valve-action of the 
pylorus, and other movements of the stomach and intestines. 

cious meal, a single sleepless night, a single passion or piece of bad news, 
will destroy it. On the other hand, a vivid hope, a cheerful resolve, an 
absorbing interest will restore it as if by magic. For in man, these lower 
officers in the nervous hierarchy draw their very breath according to the 
bidding of the higher powers. But the dependence of the higher on the 
lower is no less direct. The mutual action takes place in each line. A 
chief condition of keeping the brain healthy is to keep these unconscious 
nervous functions in full vigor, and in natural alterations of activity and 
repose. We see evidence of this law in the delightful effect of a cheerful 
walk after a depressed or irritated state of mind. Every part of the ner- 
vous system makes its influence felt by all the rest. A sort of constitu- 
tional monarchy exists within us ; no power in this small state is absolute 
or can escape the checks and limitations which the other powers impose. 
Doubtless the Brain is King, but Lords and Commons have their seats 
below and guard their privilege with jealous zeal. If the ' constitution ' 
of your personal realm is to be preserved intact, it must be by the efforts 
of each part, lawfully directed to a common end." — Hinton on Health 
and its Condition. 



46. Excess of this activity in disease ? Hydrophobia, etc. ? The difference in severity 
of the convulsions ? 

47. Another variety of reflex motions ? What are they ? What is stated of the mind 
in connection with these movements ? 



THE NERVOUS SYSTEM 243 

In these movements the mind shares no part. And it is well 
that this is so; for, since the mind is largely occupied with 
affairs external to the body, it acts irregularly, becomes 
fatigued, and needs frequent rest. The spinal cord, on the 
contrary, is well fitted for the form of work on which depends 
the growth and support of the body, as it acts uniformly, and 
with a machine-like regularity. 

48. These operations are not accompanied by consciousness ; 
for, as a general rule, the attention is only called to them when 
they become disordered. Many a person does not know where 
his stomach is situated until he discovers its position by reason 
of a feeling of distress within it, produced by giving that 
organ improper work to perform. In this manner the higher 
and nobler faculties of the mind are liberated from the simple 
routine duties of the body, and we are thus left to direct the 
attention, the reason, and the will to the accomplishment of 
the great ends of our existence. If it were otherwise, we 
could only find time to attend to our ordinary physical wants. 

49. The objects of the reflex activity of the cord are three- 
fold. In the first place, it acts as the protector of man in his 
unconscious moments. It is his unseen guardian, always ready 
to act, never growing weary, and never requiring sleep. Nor 
does its faithful action wholly cease with the cessation of life 
in other parts. In the second place, it is the regulator of 
numerous involuntary motions that are necessary to the nutri- 
tion of the body. Here its actions are entirely independent 
of the brain, and are performed in a secret and automatic 
manner. And, thirdly, it acts as a substitute, and regulates 
involuntary movements in the muscles usually under the influ- 
ence of the will. It thus takes the place of the higher facul- 
ties in performing habitual acts, and permits them to extend 
their operations more and more beyond the body and its 
material wants. 

50. The Functions of the Medulla Oblongata. — The prolonga- 

48. Consciousness in these operations ? Physical wants? 

49. How many objects may the reflex activity be said to have ? State the first. The 
second. The third. 

50. How does the medulla oblongata resemble the cord ? 



244 THE NERVOUS SYSTEM 

tion of the spinal cord within the skull has been previously 
spoken of as the medulla oblongata. It resembles the cord, in 
being composed of both white and gray matter, and in con- 
ducting sensory and motor influences. It likewise gives rise 
to certain nerves, which are here called cranial nerves (from 
cranium, the skull). All except two of these important nerves 
spring from the medulla, or the parts immediately adjoining 
it ; the exceptions are the two nerves taking part in the special 
senses of sight and smell, which nerves have their origin at 
the base of the cerebrum. 

51. The decussation, or crossing of the motor columns, has 
been previously described, when treating of the direction of 
the nerve-fibres of the cord; and the singular fact has been 
alluded to, that when one side of the brain is injured, its 
effects are limited to the opposite side of the body. One more 
fact remains to be observed in this connection, namely, this 
cross action does not usually take place in the cranial nerves. 
Accordingly, when apoplexy, or the rupture of a blood-vessel, 
occurs in the right hemisphere of the cerebrum, the left side 
of the body is paralyzed, but the right side of the face is 
affected ; this is because that part of the body is supplied by 
the cranial nerves. 

52. A portion of the medulla presides over the important 
function of respiration, and from it arises the pneumogastric 
nerve, so called because its branches serve both the lungs and 
stomach. The feelings of hunger, thirst, and the desire for 
air are aroused by means of this nerve. The wounding of the 
gray matter of the medulla, even of a small portion of it, 
near the origin of the pneumogastric nerve, at once stops the 
action of the lungs and causes death. In consequence of the 
importance of this part, it has been termed the " vital knot." 
We find, also, that its location within the skull is exceedingly 
well protected, it being quite beyond the reach of any ordinary 
form of harm from without. 



51. What final fact is observed in the crossing of the motor columns ? 

52. The pneumogastric nerve ? The feelings aroused by it ? The " Vital knot? ' 



THE NERVOUS SYSTEM 245 

53. The Functions of the Cranial Ganglia. — The uses of the 
smaller gray masses lying at the base of the brain are not 
well ascertained ; and, on account of their position, so remote 
from the surface, it would at first seem well-nigh impossible 
to study them. But, from the results following diseases in 
these parts, and from experiments upon inferior animals, they 
are becoming gradually better understood ; and there is reason 
to believe that eventually the physiological office of each part 
will be clearly ascertained and defined. It is believed, how- 
ever, but not absolutely proved, that the anterior masses, like 
the anterior roots of the spinal nerves and the anterior col- 
umns of the cord, are concerned in the production of motion ; 
in fact, that they are the central organs of that function. The 
posterior gray masses are, on the contrary, supposed to be the 
seat of sensation. 

54. The Function of the Cerebellum. — The function of the 
cerebellum, or " little brain," is the direction of the movements 
of the voluntary muscles. When this organ v is the seat of 
disease or injury, it is usually observed that the person is 
unable to execute orderly and regular acts, but moves in a 
confused manner as if in a state of intoxication. Like the 
larger brain, or cerebrum, it appears to be devoid of feeling; 
but it takes no part in the operations of the mind. 

55. The Function of the Cerebrum. — The cerebrum, or brain 
proper, is the seat of the mind ; or, speaking more exactly, it 
is the material instrument by which the mind acts ; and, as it 
occupies the highest position in the body, so it fulfils the lofti- 
est uses. All the • other organs are subordinate to it ; the 
senses are its messengers, which bring it information from the 
outer world, and the organs of motion are its servants, which 
execute its commands. Here, as in the nervous apparatus of 
lower grade already considered, the gray matter is the clement 
of power; and in proportion as this substance increases in 
extent, and in proportion to the number of convolutions in 
the hemispheres, do the mental faculties expand. 

68. The uses of the smaller gray musses :it the base of the brain ? 

54. Function of the cerebellum ? When it is diseased ? 

55. Where is the seat of the mind ? The subordination of the other organs J The gray 
matter ? 



246 THE NERVOUS SYSTEM 

56. There have been a few, but only a few, men of distin- 
guished ability whose brains have been comparatively small in 
size — the rule being that great men possess large brains. The 
relative weight of the brain of man, as compared with the 
weight of the body, does not, in all instances, exceed that of 
the inferior animals ; the canary and other singing-birds have 
a greater relative amount of nervous matter than man ; but 
man surpasses all other creatures in the size of the hemi- 
spheres of the cerebrum, and in the amount of gray substance 
which they contain. {Bead Notes 7 and 8.) 

57. It is a singular fact that this cerebral substance is insen- 
sitive, and may be cut without causing pain. The removal of 

7. The Alliance of Mind and Body. — "The regular routine of our 
daily life is the counterpart of the mental routine. A healthy man wakens 
in the morning with a flush of spirits and energy ; his first meal confirms 
and reinforces the state. The mental powers and susceptibilities are 
then at- a maximum ; as the nutrition is used up in the system they 
gradually fade, but may be renewed once and again by refreshment and 
brief remission of toil. Towards the end of the day lassitude sets in, and 
fades into the deep unconsciousness of healthy sleep. . . . The influ- 
ences that affect the body extend not only to the grosser modes of feel- 
ing, and to such familiar exhibitions as after-dinner oratory, but also to 
the highest emotions — love, anger, aesthetic feeling, and moral sensibility. 
Health keeps an Atheist in the dark. Bodily affliction is often the cause 
of a total change in the moral nature." — Bain's Mind and Body. 

8. Large Brains. — "Asa rule the size of the brain is proportional to 
the mental development in human beings. The rule is not strictly main- 
tained in every instance ; occasionally a stupid man has a larger brain 
than a clever man. But these are only individual exceptions to a prevail- 
ing arrangement. The following are the brain weights of several distin- 
guished men : 



Cuvier 64.5 oz. 

Abercrombie 63. " 

Daniel Webster 53.5 " 



Lord Campbell 53.5 oz. 

Agassiz 53.4 " 

De Morgan 52.7 " 



" The average male brain in Europeans is 49.5 oz. ; the female, 44 oz. 
Among idiots the weights have run from 27 to 8.5 oz. The brains of the 
insane are below the average of the sane. Tall men, as a rule, have 
larger brains than small men." — Bain's Mind and Body. 



56. What is stated of men in connection with the size of their brain ? With the brains 
of other animals ? 

57. Sensitiveness of the brain substance? The removal of a portion of the brain? 
State the remarkable case mentioned. 



THE NERVOUS SYSTEM 247 

a considerable quantity of the brain has taken place, as the 
result of accident, without causing death, and without even 
affecting seriously the intellect. A remarkable case of injury 
of the brain is recorded, in which, from the accidental explo- 
sion of gunpowder used in blasting a rock, the " tamping-iron " 
was driven directly through the skull of a man. This iron 
rod, three feet and seven inches long, an inch and a quarter 
in diameter, and weighing more than thirteen pounds, entered 
the head below the ear and passed out at the top of the skull, 
carrying with it portions of the brain and fragments of bone. 
The man sustained the loss of sight on one side, but otherwise 
recovered his health and the use of his faculties. Moreover, 
disease has occurred, compromising a large portion of the 
brain, without impairing the faculties of the mind, when the 
disease was limited to one side only. (Head Note 9.) 

9. The Emotions Influence the Bodily Health. — " The exciting emo- 
tions which are pleasurable, such as joy and hope, are of a kind that 
seldom tend to a dangerous excess, and may be regarded as exercising 
generally an eminently healthful influence upon the body. Hilarity is a 
great refresher and strengthener of life. Laughter is a wholesome exer- 
cise, which, beginning at the lungs, diaphragm, and connected muscles, is 
continued to the whole body, 'shaking the sides,' and causing that jelly- 
like vibration of the frame of which we are so agreeably conscious when 
under its influence. The heart beats more briskly, but with a safe regu- 
larity of action, and sends the blood to the smallest and most distant 
vessel. The face glows with warmth and color, the eye brightens, and 
the temperature of the whole body is moderately raised. With the uni- 
versal pleasurable sensation there comes a disposition of every organ to 
healthy action. When hilarity and its ordinary expression of laughter 
become habitual, the insensible perspiration of the skin is increased, the 
breathing quickened, the lungs and chest expanded, the appetite and 
digestion strengthened, and nutrition consequently increased. The old 
proverb, ' Laugh and grow fat,' states a scientific truth. The influence 
of laughter upon the body is recognized by Shakespeare, in his descrip- 
tion of the 'spare Cassius' — 'Seldom he smiles.' 'To be free-minded 
and cheerfully disposed at hours of meat, and sleep, and exercise, is one 
of the best precepts of long-lasting.' Such is the testimony of Lord Bacon 
to the favorable influence of the pleasurable emotions upon the body. 
The depressing emotions, such as fear, anxiety, and grief, are always 
fatal to health, and frequent causes of death. There is an Eastern 
apologue which describes a stranger on the road meeting the Plague 
coming out of Bagdad. 'You have been committing great havoc there.' 
said the traveler, pointing to the city. ' Not so great,' replied the Plague, 



248 THE NERVOUS SYSTEM 

58. Impressions conveyed to the hemispheres from the 
external world arouse the mental operations called thought, 
emotion, and the will. These are the godlike attributes which 
enable man to subjugate a world, and afterwards cause him 
to " sigh for other worlds to conquer ; " which enable him 
to acquaint himself with the properties of planets millions 
of miles distant from him, and which give him that creative 
power by which he builds and peoples the new worlds of 
poetry and art. 

59. All these mental acts, and many others, are developed 
through the action of the brain; not that the brain and the 
mind are the same, or that the brain secretes memory, imagi- 
nation, or the ideas of truth and justice, as the stomach 
secretes gastric juice. But rather, as the nerve of the eye, 
stimulated by the subtile waves of light, occasions the notion 
of color, so the brain, called into action by the mysterious 
influences of the immaterial soul, gives rise to all intellectual, 
emotional, and voluntary activities. 

60. The cerebrum, according to our present knowledge of 
it, must be regarded as a single organ, which produces different 
results, according as it is acted upon by the immaterial mind 
in different ways. Eecent investigations, however, seem to 
prove that the faculty of language is dependent upon a small 
part of the left hemisphere of the cerebrum near the temple. 
At least, in almost every instance where this part is diseased, 
the patient can no longer express himself in speech and writing. 
(Bead Xote 10.) 

' I only killed one-third of those who died ; the other two-thirds killed 
themselves with fright.' " — The Book of Health. 

10. Mental Exercise Necessary to Perfect Health. — "The improve- 
ment of the memory is a familiar instance of an increase of mental power 
produced by exercise ; and the beating sense of fulness and quickened 
circulation in the head induced by intense study or thought shows that 
an organic process goes on when the brain is in activity, similar to that 
which takes place in the muscular system under exercise. On the con- 
trary, when the organ is little used, little expenditure of its power and 



58. Thought, emotion, and will ? What power do they give us ! 

59. Are the brain and the mind identical ? 

60. What do we know of the cerebrum and its powers ? 



THE NERVOUS SYSTEM 249 

61. The Reflex Action of the Brain. — The reflex function of 
the organs within the skull is very active and important. Like 
that of the cord, it protects the body by involuntary move- 
ments, it regulates the so-called vegetative acts, and it takes 
the place of the will in controlling the voluntary muscles, 
when the attention is turned in other directions. The reflex 
power of the medulla governs the acts of respiration, which 
are absolutely and continuously essential to life. Eespiration 
is, as we have seen, partly under the influence of the will ; but 
this is due in part to the fact that respiration is indirectly con- 
cerned in one of the animal functions — that of speech. 

62. Reflex action also occasions coughing and sneezing, 
whenever improper substances enter the air-passages. Wink- 
ing is an act of the same sort, and serves both to shield the 
eyes from too great glare of light, and to preserve them by 
keeping the cornea moist. Looking at the sun or other strong 
light, causes sneezing by reflex action. Laughing, whether 
caused by tickling the feet or by some happy thought, and 
also sobbing, are reflex acts, taking place by means of the 
respiratory muscles. 

63. Certain of the protective reflex movements call into 
play a large number of muscles, as in the balancing of the 
body when walking along a narrow ledge, or on a slippery 
pavement. The dodging motion of the recruit, when the first 
cannon ball passes over his head, is reflex and involuntary. 

substance takes place, little blood and little nervous energy are required 
for its support, and, therefore, little is sent ; nutrition in consequence 
soon becomes languid, and strength impaired. To all these laws the 
brain is subject equally as the rest of the body. Frequent and regular 
exercise gives it increased susceptibility of action, with power to sustain 
it, the nervous energy acquiring strength as well as the vascular. Dis- 
use of its functions, or, in other words, inactivity of intellect and of feel- 
ing, impairs its structure and weakens the several powers which it serves 
to manifest. The brain, therefore, in order to maintain its healthy state. 
requires to be duly exercised.' 1 — Barlow on Physical Ed neat ion. 



61. The reflex function of the organs within the skull? The reflex power of the 
medulla? Respiration ? 

02. What else doos reflex notion occasion ? Winking ? Other examples ? 

63. Muscles called into play by certain reflex movements ? The somnambulist ? 



250 THE NERVOUS SYSTEM 

The fact that these involuntary reflex acts are performed with 
great precision, will explain why it is that accidents seldom 
befall the somnambulist, or sleep-walker, although he often 
ventures in the most perilous places. 

64. Walking, sitting, and other acts of daily life, become 
automatic, or reflex, from habit ; the mind is seldom directed 
to them, but delegates their control to the medulla and spinal 
cord. Thus a person in walking may traverse several miles 
while absorbed in thought, or in argument with a companion, 
and yet be conscious of scarcely one in a thousand of the acts 
that have been necessary to carry his body from one point to 
another. By this admirable and beautiful provision the mind 
is released from the charge of the ordinary mechanical acts of 
life, and may devote itself to the exercise of its nobler facul- 
ties. And it is worthy of notice, that the more these faculties 
are used, the more work does the reflex function assume and 
perform ; and thus the employment of the one insures the 
improvement of the other. (Bead Notes 11 and 12.) 

11. Automatic Action of the Brain. — "A large part of our mental 
activity consists of this unconscious work of the brain. There are many 
cases in which the mind has obviously worked more clearly and more 
successfully in this automatic condition, when left entirely to itself, than 
when we have been cudgeling our brains, so to speak, to get the solution. 
An instance, well authenticated, is related of a college student ; he had 
been attending a class in mathematics, and the professor said to his 
students one day : ' A question of great difficulty has been referred to me 
by a banker — a very complicated question of accounts, which they have 
not themselves been able to bring to a satisfactory issue, and they have 
asked my assistance. I have been trying, and I cannot resolve it. I 
have covered whole sheets of paper with calculations, and have not been 
able to make it out. Will you try ? ' He gave it to them as a sort of 
problem, and said he would be extremely obliged to any one who would 
bring him the solution by a certain day. This gentleman tried it over and 
over again ; he covered many slates with figures, but did not succeed. 
He was ' put on his mettle,' and determined to achieve the result. But 
he went to bed on the night before the solution was to be given in with- 
out having succeeded. In the morning, when he went to his desk, he 
found the whole problem worked out and in his own hand. He had 
risen in the night and unconsciously worked it out correctly, as the 



64. What is said of walking and other acts in connection with the office performed by 
the medulla and spinal cord ? 



THE NERVOUS SYSTEM 2%\ 

65. Effects of Alcohol upon the Brain. — The brain under the 
influence of small and occasional doses of alcohol shows no 
serious changes other than an increased supply of blood to the 
head. Very serious changes, however, result from the habitual 
use of alcohol ; the brain becomes harder and tougher than is 
natural, and its cell elements show a wasting away, its sub- 
stance appears shrunken, and an undue amount of watery fluid 
fills the cavities in the brain, in order to make up the dimin- 
ished bulk. The blood-vessels of the brain are sometimes 
found to be in a weakened condition, and from this various 
diseased conditions may follow. {Bead Note 13.) 

result proved ; and what is more curious still, the process was very 
much shorter than any of his previous trials." — W. B. Carpenter on 
Unconscious Action. 

12. The Mind should be Intelligently Cultivated. — " The cultivation 
of the mind should be carried on with judgment, and in due submission 
to the requirements of the body. If study be the duty of the youth, let 
him pursue it diligently, but with such intervals of rest and bodily exer- 
tion as may maintain good appetite and health. 

" The proportion of hours of study and bodily exercise may vary with 
the degree of mental work, the healthfulness of the room and surround- 
ing air, the natural strength of the body, and the degree of health ; but 
as a general rule it may be doubted whether any young person can sit at 
close study for more than two hours at a time without requiring bodily 
exertion to sustain vital action, and rest to recruit the mind. Two hours' 
mental work, and a quarter to half an hour's bodily exercise, will be 
quite compatible with the greatest progress in study. 

" Moreover, it may be doubted whether such a student can work with 
advantage for more than eight hours a day, in addition to the intervals of 
rest, for the issue will not turn on the number of hours devoted to work, 
but the intensity of the attention given." — Edward Smith on Health. 

13. Trembling due to Alcohol. — " Another condition is trembling due 
to alcohol. The hands are shaky, or unsteady, even when at rest, or if 
the hand is held out it is seen to vibrate slightly, or in more advanced 
condition, ' shakes like an aspen leaf.' I have seen this in a spirit-drinker, 
a barber, as almost the only symptom : he worked night ami day, in shav- 
ing, and to 'steady his hand,' partook repeatedly of spirits— -at first to 
relieve fatigue and then, because he saw that if he discontinued, his hand 
was too shaky to use the razor. Complete abstinence from alcohol ami 
strong coffee quite removed his tremblings and his desire for spirits." — 
Dr. W. 8. Greenfield. 



Gfi. How is tlu> brain ofcanged by alcohol J 



252 THE NERVOUS SYSTEM 

66. Effects of Alcohol on the Mind. — Alcohol produces an 
artificial insanity, in which, according to the quantity taken, 
the various types of mental diseases are distinctly manifest. 
The perceptions are bewildered, there is sleeplessness, loss of 
memory, delusion, clouded reasoning power, and benumbed 
moral sense following in the train of alcohol drinking. There 
is also a monomania caused by the prolonged use of alcohol — 
a craving for drink that knows no bounds, and but rarely a 
cure ; this is dipsomania, or thirst-madness. (Bead Note 14.) 

67. The Impairment of the Will. — The direct result of the 
taking of alcohol is seen in the loss of self-control. " The worst 
estate of man is that wherein he loses the knowledge and gov- 
ernment of himself." It is in the formation of the drinking 
habit that alcohol too often works the absolute ruin of its devo- 
tee, in both body and mind. It is apt to be a continuous habit, 
having for its sequel the dethronement of the will. It may be 
stated, as the rule, that after forty years of age, a man who 
has formed this habit is unequal by his own strength of will to 
abandon it. Many men of fine intellectual capacity and amia- 
ble qualities have become intemperate, and have so continued, 
as long as their efforts to get free again have not been supple- 
mented by outside and enforced restraint.* It is for such as 
these that inebriate asylums have been built. Other hard 
drinkers drift into violence and crime, and finally find a cura- 

14. Alcohol a Poison of the Intellect. — "In the normal state of a 
man's mind, all the faculties, the imagination, the judgment, the memory, 
the association of ideas, are regulated by another superior faculty, viz., 
the attention. The attention of the will is the man himself ; it is the ego 
which, being in the full possession of the resources of which it disposes, 
takes them where it will, when it will, to do whatever it pleases. Now in 
drunkenness, even at the very beginning, the will and the attention have 
disappeared. Nothing is left but the imagination and the memory, which, 
left to themselves, without regulation and without guides, produce the 
most irrational results. " — Charles Bichet. 

* " Alcohol in small doses super-excites certain intellectual faculties — 
the imagination, the memory, and the association of ideas ; but it para- 
lyzes others, especially the will, the reflection, and judgment. Yet, with 



66. What changes are noticed in the mind ? 

67. Give effect of alcohol upon the will. 



THE NERVOUS SYSTEM 253 

tive restraint within prison walls. The benumbing effects of 
drinking habits upon the moral being of man is universally 
known. " All delicacy, courtesy, and self-respect are gone ; the 
sense of justice and of right is faint or quite extinct ; there 
is no vice into which the victim of drunkenness does not easily 
slide, and no crime from which he can be expected to refrain. 
Between this condition and insanity there is but a single step," 
and death, in a worldly sense a deliverance, in spite of many 
an effort to rally, " terminates the miserable scene ; one by one 
lights have been removed from the banquet of folly, and the 
last is now extinguished." {Bead Notes 15 and 16.) 

68. An illustration of the disadvantage of drunkenness to 
the moral tone of a community may be drawn from the results 
of the labors of Father Mathew, about forty years ago, as a 

a stronger dose all trace of intelligence disappears. When old Sly is 
stretched on the ground insensible from drink and snoring in the mud, 
he excites compassion and disgust : 

monstrous beast ! how like a swine he lies ! 

Grim death, how foul and loathsome is thine image ! " 

Charles Bichet, in Bevue des Deux Mondes. 

15. Drunkenness and Insanity. — "The connection between drunken- 
ness and crime and drunkenness and poverty, is close and unvarying in 
its effect upon society. The remarkable increase of insanity in recent 
years may in part be traced to the use of intoxicating beverages. It has 
been asserted that at least seven-tenths of all the crime and poverty and 
calamity to the people of the United States spring from the abuse of 
liquors." — Dr. J. E. Beeves. 

16. The Effects of Mild Stimulation. — " Words of caution to young 
men concerning the injurious effects of tobacco, as well as indulgence in 
wine or the pleasures of the table, elicit, in ninety-nine out of one hun- 
dred cases, the reply, ' It does not hurt me.' Does not hurt you ! Wait 
and see. In years to come, when you ought to be in your prime, you 
will be a poor, nervous, irritable, nerve-dried creature. Your hands will 
tremble, your head will ache, your sleep be fitful and disturbed, your 
digestion impaired— in short, the unnatural and transient pleasure at 
one end of your life will be more than counterbalanced by the discomfort 
and misery at the other. It is a truth of the greatest moment, which 
ought to be so impressed upon the mind as to be always rising up within 
it, that transgressions of the laws of health, not punished at one end of 
life, are sure to be at the other:'— J. B. Black on the Ten Laws of 
Health. 

68. Giye results of Father Mathew'S work. 



254 THE NERVOUS SYSTEM 

temperance reformer. In the five years — 1838-1842 — the 
consumption of whiskey in Ireland fell 50 per cent. ; the crimes 
of violence falling from 64,520 to 47,027, and executions from 
59 in the first year to 1 in the last year. {Read Note 17.) 

69. The Poisonous Effects of Alcohol. — Alcohol is, in the 
main, a narcotic poison in its effect upon human beings, 
although the visible results vary immensely according to the 
quantity taken. If a sufficient quantity is taken to cause any 
visible result, a condition known as stimulation is observed.* 
If an extremely large dose is taken, a state of stupor follows, 
and death has been known to result in some cases. Between 
these two extremes there may be a variety of manifestations. 
As a stimulant, it appears to many to have a kindly action, to 
cause a glow and sense of warmth, to increase muscular activity, 
and to make the mind and organs of speech more nimble. 

17. Alcohol and Crime. — "Thirty years of judicial experience have 
taught me that of the crimes which judges are called upon to try, and 
upon which sentences of the law are pronounced, more than eight-tenths 
of them involving any degree of violence in their character are directly 
traceable to the liquor shops. How often have I had young men look up 
at me when I asked them what they had to say why the sentence of the 
law should not be pronounced, and declare, 'I should never have done this 
crime if it were not for drink. Rum was my ruin ; rum struck the blow, 
and not my hand, that killed the man for whose death I am tried ; rum 
has caused me to beat my wife, and injure my helpless child, and to do 
the act which now confines me to a prison." — Judge Noah Davis. 

* " Suppose, for instance, you measure your muscular strength with a 
' health lift ' or dynamometer (by which muscular exertion can be accu- 
rately measured), and then take some of the drink in the strength- 
inspiring power of which you have most confidence, and when you are 
most exhilarated by it, and feel as if you could shoulder a large fragment 
of Mount Olympus, measure your strength again. The drink has fooled 
you, that is all. You felt that you were stronger than natural ; you find 
that the narcotic has been true to its paralyzing nature, and that you are 
weaker. Then, after a time, when the drug has spent itself, and reaction 
(so called) comes on, and you feel weak and prostrated, measure your 
strength once more. Fooled again ; the stuff has fooled you twice. 
When you felt yourself strong you were weak, and now when you feel 
yourself weak, you find yourself stronger — your natural strength is 
returning, and what you have called reaction is in reality recovery from 
the weakening effects of the narcotic." — Dr. A. F. Kinne. 



69. Poisonous effects of alcohol ? 



THE NERVOUS SYSTEM 255 

70. Chronic Alcoholism and Delirium Tremens. — When per- 
sons become habituated to the over-indulgence of alcohol in 
large quantities, its effects produce serious and permanent 
changes in the general nervous system, the various manifes- 
tations of which are spoken of as chronic alcoholism. They 
manifest themselves chiefly in a disturbance of the various 
brain functions. These persons usually suffer from sluggish 
brain action, and a serious disturbance of many of the brain 
functions, such, for instance, as loss of memory. There is 
usually present trembling of the hands, trembling of groups of 
muscles in other parts of the body ; and they are unable to 
endure any bodily fatigue. When a person has been consum- 
ing large quantities of alcohol for some time, a sudden and 
very violent delirium may result. To this has been given the 
name of delirium tremens, from the fact that it is accompanied 
by more or less violent trembling of the entire body. It is 
extremely dangerous to life, often producing death, and in 
many instances insanity. 

71. Tobacco and its Effects. — Tobacco, familiarly known as 
"the weed," is an annual plant said to be a native of America. 
It grows to a height of several feet, with leaves of a pale green 
color. These leaves, when dried, are made into cigars, chewing 

18. " Here is a company of 'jolly good fellows,' all standing on their 
feet, their faces red and radiant, and all swinging their arms and talking 
at once. These men have been taking alcohol, and, surely, you will say, 
it has stimulated them. But if you will attend for a moment to what 
they are saying, you will see that there is no true brain-stimulation about 
it. We shall be reminded rather of what Addison says of the difference 
between the mind of the wise man and that of the fool : There are infi- 
nite, numberless extravagancies, and a succession of vanities which pass, 
through both. The great difference is that the first knows how to pick 
and cull his thoughts for conversation, by suppressing some and com- 
municating others ; whereas the other lets them all indifferently fly out 
in words.' The case with these revelers is precisely this. The poison 
which they have taken has paralyzed their conservative faculties, and the 
talking propensity is running on without anything to hold it in cheek and 
regulate it." — Br. A. F. Kinne. 



70. Describe the tobacco plant. 

71. What is its effect upon the nerves ? 



256 THE NERVOUS SYSTEM 

and smoking tobacco, and snuff, which are extensively used 
throughout the civilized world 

72. Tobacco as a Poison. — Tobacco is a poison to the young, 
and is far more hurtful to the adult than is generally supposed. 
It may be stated, as a rule, that there are few persons who use 
it habitually that do not suffer injury from it. The injury is 
mainly caused by what is known as " nicotine," one of the nar- 
cotic poisons, and particularly prominent in tobacco. Some of 
the effects of its limited use are nausea, vomiting, vertigo, and 
weakness ; and its prolonged use, by those who are sensitive 
to it, often results in convulsions and other like symptoms, 
together with an irritability and weakened condition of the 
heart, known to physicians as the "tobacco-heart." 

73. Effects on the Young. — Of the pernicious influence of 
the use of tobacco upon the young, the testimony of the Naval 
and Military Academies of the country is very decided. It 
has at times been allowed in both institutions, but at present 
it is forbidden, on ^he ground that its use is attended with 
serious damage to health. It is stated that its prohibition 
at the Naval Academy in 1881 was received with unanimous 
approval by the officers in charge, and with "great joy by 
many of the cadets." Tremor of the muscles, caused by smok- 
ing, was very noticeable in the drawings that form so impor- 
tant a part of the cadets' work. A teacher of drawing of 
fourteen years' experience has said that he can always tell 
from the character of the lines in the drawings, whether or 
not the pupils use tobacco. Its avoidance has resulted in the 
reduced number of minor ailments that swelled the sick-list in 
years when its use was unrestricted. Athletes and other per- 
sons who engage in running matches and the like, are com- 
monly not allowed to use either alcohol or tobacco while they 
are " in training " ; their use interferes with the fullest devel- 
opment of muscular strength. (Bead Note 19.) 

19. "The end of all science is to secure long life and good health to 
the individual and the race, and it ought to be a part of the rational 
creed of every good man and woman to abjure the use of tobacco, and 
keep others from falling into the vice." — Dr. C. B. Drysdale. 

" Tobacco is certainly not a food for man, nor has it much value as a 

72. Tobacco as a poison ? 73. The effects of tobacco on the young ? 



THE NERVOUS SYSTEM 257 

74. Cigarette-Smoking. — This form of taking tobacco is in- 
jurious in two particulars that do not apply to the other forms. 
The smoker of cigarettes, either voluntarily or involuntarily, 
takes into his lungs a very large amount of smoke, and with 
it that hurtful element, carbonic oxide. Again, there is an 
excessive amount of adulteration of the tobacco in cigarettes ; 
and one substance, opium, is largely so used, and is extremely 
injurious. 

75. Snuff-Taking. — In addition to the hurtful effects of 
tobacco generally, snuff -taking is notoriously injurious to the 
senses of smell and taste, and to the voice. 

76. Narcotics. — The term narcotic is applied to different 
substances derived chiefly from the vegetable kingdom, which 
have the wonderful property of quieting pain and causing 
sleep. Next in importance to alcohol, which belongs to the 
narcotics, are opium (and its preparations), chloral hy i rate, 
hasheesh, and chloroform. 

77. Opium. — Opium is the thickened juice of the poi py- 
plant of India, and is commonly regarded as the most impor- 
tant of the narcotics. Its active principle is morphine, whic^. 
gives the soothing property to laudanum, paregoric, and Dover's 
powders. It is also used in nostrums to put infants to sleep : 
but, unwisely used, often brings on a sleep that knows no 
waking. 

78. Effects of Opium. — Opium is particularly injurious to 
the young, even small doses sometimes producing alarming 
symptoms. Upon adults the external effects are not as notice- 
medicine. The tobacco-worm is the only animal known to thrive upon 
it." — J 7 . H. Hamilton. 

"An illustration of the depressing influence of tobacco is given by 
Dr. Jacob Bigelow, who states that soldiers, when wishing to shirk duty 
and get on the sick-list, sometimes succeed in bringing on the symptoms of 
alarming sickness by wearing a piece of tobacco under each armpit. The 
skin absorbs sufficient of the poison to affect the system to a marked 
degree." 

74. What is said of cig-arotto-smoking? 77. What is opium ? 

75. Snuff-taking ? T8, What are the effeots of using opium J 

70. What do you understand by narcotics ? 



258 THE NERVOUS SYSTEM 

able as are those of alcohol, but the mind is more deeply stirred 
and the flow of ideas more copious. 

79. Danger from Opiates. — The use of opium for relieving 
pain has been known for hundreds of years. The enchanting 
sense of relief to suffering wrought by opiates leads to the mor- 
phine habit, commonly called opium-eating. It will be seen, 
therefore, why such great care is exercised by physicians in 
administering opiates, lest their patients afterward fall into the 
habit of taking them without medical advice. (Bead Note 20.) 

80. Physiological Effects of Opium. — The frequent use of 
opium disturbs and weakens the stomach as well as the other 
digestive organs ; hence we invariably find the opium-eater to 
be a lean, yellow, sallow person. His muscular and mental 
powers are impaired, and his will is terribly enfeebled. This 
dreadful habit can be broken only with unspeakable suffering 
to its victim. 

81. Chloral Hydrate. — Chloral hydrate, commonly called 
chloral, is produced from alcohol ; but its power as a sedative 
was not generally known until within the past twenty years. 
It also is a destroyer of appetite as well as of digestion, unless 
prescribed in proper doses, and the unfortunates once given 
over to it find themselves unable to sleep without its continued 
use. It should never be taken except under the direction of a 
physician. 

20. ' ' The opium-eater loses none of his moral sensibilities or aspira- 
tions ; he wishes and longs as earnestly as ever to realize what he believes 
possible, and feels to be exacted by duty ; but his intellectual apprehen- 
sion of what is possible infinitely outruns his power, not of execution 
only, but even the power to attempt. He lies under the weight of incu- 
bus and nightmare ; he lies in sight of all that he would fain perform, 
just as a man forcibly confined to his bed by the mortal languor of a 
relaxing disease, who is compelled to witness injury and outrage offered 
to some object of his tenderest love ; he curses the spells which chain 
him down from motion ; he would lay down his life if he might but get 
up and walk ; but he is pow T erless as an infant, and cannot even attempt 
to rise." — Be Quincey's Confessions of an Opium-Eater. 



79. What the danger ? 

80. What effect upon the system ? 

81. What do you know of chloral hydrate ? 



THE NERVOUS SYSTEM 259 

82. Hasheesh. — Hasheesh, the juice of Indian hemp, is said 
to be used by millions of the inhabitants of Asia. It is not 
known much in the western countries. In the East the excite- 
ment caused by its use takes the form of furious madness, lead- 
ing its victim to commit acts of violence and murder. Hence 
the term " hasheeshers " in our language has come to be synony- 
mous with assassins. (Bead Note 21.) 

83. Cocaine. — Cocaine is a drug, derived from the Coca 
plant, a native of Peru, South America. Its use in medicine 
is — like many of the dangerous drugs — of great value. By 
injection under the skin, we can render parts of the body 
entirely insensitive to pain, so that quite extensive operations 
may be undertaken without producing any pain. It is used 
also in operations upon the eye, mouth, and nose, where it pro- 
duces its effect when a solution of it is dropped on the surface. 
Because of its powerful effect in relieving pain, many persons 
have become addicted to its use. In many it also produces 
pleasurable sensations, to repeat which, they have to take 
larger and larger doses, and very soon become slaves to its 
use. It rapidly undermines the general health, and soon leads 
to death if its use is not speedily checked. 

84. Chloroform. — Chloroform, another product from alcohol, 
is used by inhalation when surgical operations are to be per- 
formed. As it is very powerful and subtile in its action, the 
unskilful use of it is dangerous in the extreme. The habit of 
taking chloroform by those who are great physical sufferers, or 
whose constitutions have been wrecked by the use of other 
narcotics, should be discouraged. It too often happens that 
the career of such is short, for the drug may easily be taken 
in excess and so cause death. 

21. " As everybody knows, the intoxication caused by alcoholic liquors, 
by hasheesh, by opium, after a first period of excitement, brings about a 
notable impairment of the will. The individual is more or loss con- 
scious of this ; other persons see it more clearly. Soon — especially under 
the influence of alcohol — the weakening of the will becomes excessive. 
The extravagances, violences, and crimes committed in this state are 
innumerable." — Dr. T. Bitot. 



82, What is hasheesh ? Its use ? 88. Cocaine? Its use ? 84 Chloroform ,; Its use 



260 THE NERVOUS SYSTEM 

85. Sleep Produced by Narcotics. — Opium and the opiates 
have the power of quieting the activity of the brain, and of 
compelling sleep. This may be a blessed action if skilfully 
applied by the physician, but not so applied it is the source of 
infinite peril. The sleep so caused differs from natural, restful 
slumber, especially in the fact that the after-effects are com- 
monly depressing and disturbing to the brain to the extent of 
being harder to bear than the wakefulness on account of which 
the drugs are taken. Very young persons are especially 
subject to injury by sleep-producing medicines; and many 
are the deaths that have been caused among infants by the 
giving of "soothing syrups," "cordials," and "anodynes," 
that are so freely sold for the purpose of compelling sleep. 

86. Results of the Use of Narcotics. — The use of any of 

these narcotics, without proper medical advice, is their abuse. 
In this way they become powerful for harm. They are no 
longer remedies, but poisons. Self-prescribed, they have a 
thousand times been the instrument of unintentional suicide. 

87. The craving for narcotics is found in many nervous people, 
or in those whose general health is not good. They experience 
such a great relief from the use of narcotics, in simple ner- 
vousness, in pain, or in insomnia, that they naturally wish to 
repeat these pleasant experiences. This desire soon develops 
into a craving like as that of the drunkard for his alcohol. 
Such a person should place himself under the care of a phy- 
sician. 

88. Effects of Heredity. — There seems to exist ima number 
of people a natural desire for alcohol, or for any one of the 
drugs and narcotics enumerated above. Upon inquiry, it will 
often be found that their parents or grandparents had similar 
tastes, and we therefore speak of them as having hereditary 
tastes or desires. Persons who discover in themselves this 
hereditary liking for either alcohol or drugs should never use 
either of them, for fear of becoming addicted to their use. 

85. Sleep produced by narcotics ? Danger of using " soothing syrups," etc. ? 

86. Self-prescribed narcotics ? 
8T. The craving for narcotics ? 
88. Effects of heredity ? 



THE NERVOUS SYSTEM 



2G1 



TOPICAL OUTLINE 



f Pia mater . 
Coverings J Arachnoid . 

I Dura mater 
' Cerebrum . 



« Structure ■{ _ . „ 
pq Cerebellum 



Medulla . . 
f Cerebrum . 
Functions Cerebellum 

i 

I Medulla . . 



Cerebro- 
spinal . . . 

NERVOUS 
SYSTEM . 



[ Sympathetic 

f Cellular . . 
I Fibrous . . 

| Fresh . . . 
I After death 

I Afferent . . 

< Efferent . . 
t Mixed . . . 



NERVE SUB- 
STANCE . . . 

NERVE 
FIBRES . . . 



NERVES 



f Inner, delicate, vascular. 
-I Closely invests the brain. 
[ Follows all the convolutions. 

A serous membrane. 
I Tough, fibrous. 
J Outer surface rough, and in contact with the 

skull. 
I Inner surface smooth. 
I Right and left hemispheres. 
J Surface convoluted. 
j Fills all upper portion of cranium. 
I Gray matter outside. 
j Right and left hemispheres. 
J Surface drawn into folds. 
| Fills occipital portion of cranium. 
I Gray matter outside. 
\ Connects the brain with the cord. 
' Gray matter inside. 
{ Chief seat of sensation. 

\ The organ of the will and voluntary motion. 
I The seat of the intelligence. 
j The seat of muscular sense. 
1 Co-ordinates muscular movements. 
[ Governs the muscles of respiration and deglu- 
J tition. 

I A conducting medium between the brain and 
L the cord. 

I Brain and its nerves. 



Consists of 



/ Spinal cord and its nerves. 
\ Organs of sense. 



f Consists of 



I Fibres distributed to , 

I Voluntary muscles. 

f Double chain of ganglia, on 

each side of the vertebral 

column. 

I Various disconnected ganglia. 

| The internal organs. 

Fibres distributed to i The walls of blood- 

[ vessels. 

Grayish — in nerve centres, 
i Nerve fibres —forms nerves, and enters into 
* the structure of nerve centres. 

A simple semitransparent filament. 
\ A tube, containing a white opaque sub 
' stance. 

\ Convey impressions to a centre only. 
' Also called scHsortj nerves. 
["Convey impressions from r centre only. 
{ Fibres terminate in muscular fibres 
(. Also called motor nerves. 

Contain both afferent and efferent fibres. 



262 



THE NERVOUS SYSTEM 



THE SPINAL 
CORD .... 



Reflex action 



j In the spinal canal formed by the vertebral 

I column. 

f About eighteen inches. 

-\ Extends from the medulla oblongata to the first 

[ lumbar vertebra. 

About one-third of an inch. 
f Pia mater — delicate, vascular. 
I Arachnoid — serous, forming a loose bag. 
\ Dura mater — tough, fibrous. 
| (A layer of fatty tissue lies between the dura 
I- mater and the bony canal.) 
f Gray matter internal. 
I White matter external. 
-j Anterior fissure. 

I Posterior fissure — deeper and narrower. 
*■ Central canal — microscopic. 

Thirty-one pairs — between the vertebrae. 

Crowded at the lower extremity of the cord — 

cauda equina. 

| Each trunk formed by the union of two i^oots. 

-d , < Anterior — motor. 
I Roots < „ , . 

' Posterior — sensory. 

f Conduction of impressions. 

J A centre for reflex action (gray matter) . 

I Sensory fibres — cross as they enter the .cord. 

I Motor fibres — cross in the medulla oblongata. 
f A disturbed condition of sensory fibres — 
J Conducted to a nerve centre — 

j Reflected by the nerve centre along motor fibres to their 
j terminations in muscles — 
i Muscular contraction. 



I Position . 

Length . 
Thickness 

Coats . . 



Structure 



Nerves . 



QUESTIONS FOR TOPICAL REVIEW 

PAGE 

State fully what is meant by the term vegetative function 217 

To what does man owe his position as the head of the animal creation ? 218 
What can you state on the subject of special organs for separate 

functions ? 219 

Describe, as fully as you can, the structure of the nervous system. 218, 219 

Describe the brain, its location, size, shape, and structure 219-222 

Describe the brain proper, or cerebrum 222, 223 

Describe the little brain, or cerebellum 224, 225 

Describe the spinal cord 227, 228 

What are the spinal nerves, and how are they arranged ? 228 

What is the character and substance of their tissues ? , 228, 229 

State and illustrate how the nerve-fibres perform their office .... 229, 230 

Describe the sympathetic system of nerves 230, 231 

State the properties of nervous tissue, and illustrate 231-233 

Explain the functions of the nerves 233 

What is meant by transient paralysis of a nerve ? Illustrate 234, 235 

What can you state of the rate of message-motion along a nerve?. . 235 



THE NERVOUS SYSTEM 263 



PAGE 

17. What are the functions of the spinal cord ? 236 

18. State what you can of the form of paralysis known as paraplegia. . 236 

19. What experiments, with results, upon the spinal cord are noted ?. 236, 237 

20. Give the direction of fibres of cord 237, 238 

21. How does the left side of brain feel pain in right hand ? 238 

22. What is understood by the reflex action of the cord ? 238 

23. What experiments are mentioned to prove this power of the cord ? 238-240 

24. What are the uses of the reflex action of the cord ? 240-243 

25. What is the medulla oblongata and its function ? 243, 244 

26. What can you state of the functions of the cranial ganglia ? 245 

27. What are the functions of the cerebellum ? 245 

28. What is the function of the cerebrum ? 245 

29. In what way does the size of the brain generally indicate the 

character ? , 246 

30. What facts show that the gray substance of the brain is insensi- 

tive ? 246, 247 

31. Upon what does the faculty of language seem to depend ? 248 

32. Of what importance is the reflex action of the brain ? , 249 

33. In what ways is this importance made manifest ? 250 

34. Give the effects of alcohol upon the brain 251 

35. How does it affect the mind ? 252 

36. What is said of the effect upon the will? 252 

37. How is the whole system affected ? 254, 255 

38. What is said of tobacco ? 255-257 

39. Define and illustrate the term narcotic 257 

40. Give the statement regarding opium 257 

41. State what you can of chloral 258 

42. What is hasheesh and its effect? .' 259 

43. What is said of chloroform ? 259 

44. Give general results of use of narcotics 260 



CHAPTER X 

THE SPECIAL SENSES 

The Production of Sensations — Variety of Sensations — General Sensi- 
bility — Pain and its Function — Special Sensation, Touch, Taste, 
Smell, Sight, and Hearing — The Hand, the Organ of Touch — The 
Sense of Touch — Delicacy of Touch — Sensation of Temperature and 
Weight — The Tongue, the Organ of Taste — The Nerves of Taste — 
The Sense of Taste and its Belations with the other Senses — The 
Influence of Education on the Taste — The Nasal Cavities, or the 
Organs of Smell — The Olfactory Nerve — The Uses of the Sense of 
Smell — The Sense of Sight — Light — The Optic Nerve — The Eye- 
ball and its Coverings — The Function of the Iris — The Sclerotic, 
Choroid, and r , Retina — The Tears and their Function — The. Move- 
ments of the Eyeball — The Function of Accommodation — The Sense 
of Hearing and Sound — The Ear, or the Organ of Hearing — The 
External, Middle, and Internal Ear 

1. Production of Sensations. — We have already seen that the 
true centre of sensation is some organ within the skull, proba- 
bly among the gray masses at the base of the brain ; but the 
mind never perceives impressions at that point ; on the con- 
trary, it always refers them to the external organs of sensa- 
tion. Hence, it is convenient to say that those outer parts 
possess the property of sensibility. For instance, we say that 
we hear with the ear, taste with the tongue, and feel with the 
fingers. That this is not the exact truth is proved by the fact 
that, whenever the nerve connecting one of these organs with 
the brain is severed, it at once loses its capacity for sensation. 

2. Consciousness, another faculty of the brain, is necessary 
to complete a sensation. During sleep, and in other uncon- 



1. True centre of sensation ? Place of the mind's impressions ? What is it convenient 
to say ? What further is stated ? 

2. Consciousness ? During sleep ? In profound insensibility ? 

264 



THE SPECIAL SENSES 265 

scious states, the usual impressions are presented to the ear, 
the nose, and the skin; but they fail to excite sensations, 
because the nerve-centres are inactive. In profound insensi- 
bility, from chloroform or ether, a limb may be removed with- 
out occasioning the least feeling. 

3. Variety of Sensations. — All animals have some degree of 
sensibility. It is, of course, feeble and indistinct in the lower 
forms of life, but increases in power and variety as we ascend 
the scale. In the earth-worm, the nervous system is very 
simple, the sensibility being moderate and alike in all parts; 
hence, if its body be cut into two pieces, each piece will have 
the same degree of feeling as before. As we approach man, 
however, the sensations multiply and become more acute; the 
organs are more complex, and special parts are endowed with 
special gifts. These special organs cannot be separated from 
the rest of the body without the loss of the functions they are 
designed to exercise. 

4. The lowest form of sensation — that of simple contact — 
is possessed by the lowest of the animal creation. The highest 
forms are those by which we are enabled to know the .proper- 
ties of external objects, such as shape, size, sound, and color. 
A variety of means of communicating with the outer world is 
the necessary possession of a high intelligence. Sensations are 
modified by use. They become more acute and powerful by 
moderate exercise, or they are dulled by undue excitement. 
The former is shown by the acute hearing of the Indian, by the 
sharp sight of the sailor, and by the delicate touch of the 
blind. The latter is exemplified by the impaired hearing of 
the boiler-maker, and the depraved taste of hi m who uses 
pungent condiments with his food. Again, impressions habitu- 
ally presented may not be consciously felt, as is the case with 
the rumbling of carriages in a neighboring street, or the regular 
ticking of a clock. All sensations become less vivid with the 
advance of age, especially hearing and vision. 



8. Sensibility in animals ? In the earth-worm ? in man? 

4. The lowest, form of sensation ? The highest} Sensations, how modified I What 
further can you state as to habitual impressions ? 



266 THE SPECIAL SENSES 

5. General Sensibility. — There is a property possessed by 
nearly all parts of the human body which we call general 
sensibility. We have recently seen that the brain is wholly 
insensitive, and may be cut or pinched without pain. The 
same is true of the nails, hair, the scarf-skin or external cover- 
ing of the body, and a few other structures. In these parts no 
nerves are found. On the other hand, the sensibility of the 
true skin, and of mucous membranes, as of the eye and nqse, is 
exquisite, these organs having a large, supply of sensory nerve- 
fibres. The bones and tendons have less of these fibres, and 
are only moderately sensitive. 

6. The sensibility of any part of the body, then, depends 
upon the number of nerves present ; and, as a rule, the nervous 
supply is proportional to the importance of the part, and to its 
liability to injury. When, therefore, a surgical operation is 
performed, the most painful part of it is the incision through 
the skin — the muscles, cartilage, and bone being comparatively 
without sensation. Hence, if we could benumb the surface, 
certain of the lesser operations might be undergone without 
great inconvenience. This is, in fact, very successfully accom- 
plished by means of the cold produced by throwing a spray of 
ether, or of some other rapidly evaporating liquid upon the 
part to be cut. 

7. Tickling is a modification of general sensibility. At first 
it excites a pleasurable sensation, but this soon passes into 
pain. It is only present in those parts where the sense of 
touch is feeble. But all impressions are not received from 
without ; there are, also, certain internal sensations, as they are 
called, which depend upon the^ condition of the internal organs, 
such as appetite, hunger, thirst, dizziness when looking down 
from some lofty position, drowsiness, fatigue, and other feel- 
ings of comfort or discomfort. General sensibility, whether of 
the internal or external organs of the body, chiefly depends 

5. General sensibility ? What hare we seen as regards the brain ? Of what other 
structures is the same true ? 

6. The cause of sensibility ? Painful part in a surgical operation ? Benumbing the 
surface ? How done by ether ? 

7. Tickling? Internal sensations ? The nerves of general sensibility ? 



THE SPECIAL SENSES 267 

upon the sensory fibres of the spinal nerve. The face, how- 
ever, is supplied by the sensory cranial nerves. The sympa- 
thetic system has a low grade of feeling in health, but disease 
in the parts served by it arouses an intense degree of pain. 

8. The Sensation of Pain. — What then is pain? Is it iden- 
tical with ordinary sensibility ? There seems to be some 
necessary connection between the two feelings, for they take 
place through the same channels, and they are alike intense in 
the same situations. But sensibility habitually contributes to 
our sources of pleasure — the very opposite of pain ; hence, 
these feelings cannot be identical. 

9. Pain must, therefore, "be a modification of the general 
sensibility which follows an excessive degree of excitement of 
the nerves, there being a natural limit to the amount of stimu- 
lation which they will sustain. So long as this limit is observed, 
the part excited may be said to be simply sensitive ; but when 
it is exceeded, the impression becomes painful. This difference 
between sensibility and pain is well shown by the effects of 
sunlight upon the eye. The indirect illumination of the sun 
arouses only the former feeling, and is indispensable to our 
comfort and existence, while the direct ray received into the 
eye occasions great pain. 

10. The Uses of Pain. — The dread of pain is a valuable 
monitor to the body. It puts us on our guard in the presence 
of danger, teaches moderation in the use of our powers, indi- 
cates the approach of disease, and calls attention to it when 
present. The word disease, in fact, according to its original 
use, had reference simply to the pain, or want of ease, which 
commonly attends disordered health. When we observe the 
serious mishaps which occur when sensibility and pain are 
absent, we cannot fail to appreciate its value. For example, a 
paralytic, in taking a foot-bath, forgets to test its temperature, 
and putting his limbs into water while it is too hot, is severely 
scalded without knowing it. 

8. Connection between pain and sensibility ? 

9. Explain the difference between pain and sensibility. 

10. Dread of pain ? How may its value be appreciated * Kxainple * 



268 THE SPECIAL SENSES 

11. A traveler, overcome by cold and fatigue, lies down and 
falls asleep near a large fire, and when he is aroused in the 
morning, it is discovered that one of his feet has been insen- 
sibly destroyed. A grain of sand, lodging in an insensitive 
eye, may cause inflammation, and even the loss of sight. If 
intense light were not painful to the eye, many a child would 
innocently gaze upon the glories of the sun to the ruin of his 
sight. 

12. Pain is, indeed, a present evil, but its relations with the 
future prove its mission merciful. Painful impressions cannot 
be recollected from past experience, and they cannot be called 
into existence by the fancy. Considered in the light of results, 
pain has a use above that of pleasure ; for, while the immod- 
erate pursuit of the latter leads to harm, the tendency of pain 
is to restrict the hurtful courses of life, and in this manner to 
protect the body. 

13. The relations of pain to pleasure are thus described by 
the eminent physiologist, Magendie : — "By these sensations 
Nature induces us to concur in the order which she has estab- 
lished among organized beings. Though it may appear like 
sophistry to say that pain is the shadow of pleasure, yet it is 
certain that those who have exhausted the ordinary sources of 
pleasure have recourse to the causes of pain, and gratify them- 
selves by their effects. Do we not see in all large cities, that 
men who are debauched and depraved find agreeable sensations 
where others experience only intolerable pain? " {Bead Note 1.) 

1. Pain is "Nature's Harbinger of Mischief." — "It must, there- 
fore, be evident that pain is, under certain circumstances, really beneficial. 
It is often a great boon to have a sensitive stomach ; for those who suffer 
pain after food are less apt habitually to err in diet, and thus to become 
dyspeptic or gouty, than those whose organs receive everything uncom- 
plainingly. Pain in the stomach is frequently due (in well-to-do people) 
to the fact that they won't work and will eat ; not that the stomach itself 
is weak (as they think), but that the supply of food being greater than 
the demand, the system becomes overstocked. In dyspepsia the cause is 
very often far away, and the stomach is no more the cause of the malady 



11. The case of the traveler ? Grain of sand? The sun and child ? 

12. Mission of pain ? Painful impressions compared with those of pleasure? 

13. What does Magendie say of the relation of pain to pleasure ? 



THE SPECIAL SENSES 269 

14. As to painful sensation among the inferior animals, the 
plan of Nature seems to be, that the higher the intelligence of 
the creature, and the more complete its power of defence, the 
more acute is its sensibility. We infer, therefore, that animals 
low in the scale of existence, and helpless, are not very liable 
to suffer pain. 

15. Special Sensation. — The sensations of simple contact 
and pain are felt by nearly all parts of the system, whether 
external or internal, and are the necessary consequence of the 
general sensibility; but, so far as the objects which surround 
us are concerned, these impressions are vague and passive in 
character, and inform the mind of none of the properties or 
powers of these objects. Besides these feelings, therefore, 
man is endowed with certain special sensations, which are 
positive and distinct in character, and which he can call into 
exercise at will, and employ in the pursuit of knowledge. For 
reasons relating to the original constitution of the body, these 
sensations are to be regarded as modifications of the general 
sensibility already alluded to, constructed with special refer- 
ence to the different forces of Nature of which we have any 
knowledge, such as heat, motion, gravity, sunlight, and the 
like. {Bead Note 2.) 

than the big toe is of the gout ; but if the stomach gave no signs of per- 
turbation, the evil would be allowed longer to exist unnoticed. We should 
always give early attention to pain, and discover its causes before they 
become too complex to be unraveled, and before the derangement which 
its presence indicates becomes permanent. The following incident well 
illustrates the extent to which pain may be dependent on fancy : ' A 
butcher was brought into the druggist's from the market-place opposite, 
laboring under a terrible accident. The man, on trying to hook up a 
heavy piece of meat above his head, slipped, and the sharp hook pene- 
trated his arm so that he himself was suspended. On being examined, 
he was pale, almost pulseless, and expressed himself as suffering acute 
agony. The arm could not be moved without causing excessive pain, and 
in cutting off the sleeve he frequently cried out ; yet, when the arm was 
exposed, it was found quite uninjured, the hook having only traversed 
the sleeve of the coat!' The sensation lien 1 was perfectly real, but 
originated in a change of the brain and nerves, instead of in the external 
senses. " — Notes on Pain. 



14. The law of Nature as regards painful sensations among animals * 

15. The sensation of contact and pain ? Special seusations o( man i How regarded ': 



270 THE SPECIAL SENSES 

16. These distinct and active faculties are termed the 
special senses, and are five in number, viz., Touch, Taste, 
Smell, Sight, and Hearing. For the exercise of these senses, 
special organs are furnished, such as the hand, the tongue, the 
nose, the eye, and the ear. The manner in which the nerves 

2. The Mutual Relations of the Special Senses. — "A blind man, 
attempting to express his notion of scarlet, said it resembled the sound of 
a trumpet. We are constantly reminded of the impressions of one sense 
by the operations of another. To my ear the bass note in music is what 
a dull black is to the eye. The reverberations of deep thunder seem like 
boulders with worn angles — with profiles blunt and irregular, as if drawn 
by the jerking pencil of the lightning ; and one who never had the pleas- 
ure of seeing stars from a blow on the head may get a tolerably correct 
idea of that kind of galaxy by snuffing at a bottle of volatile salts. 

' ' Language is full of effort to report the impressions of one sense by 
the symbols of another. We say that an apple is sweet, that a rose is 
sweet, a face is sweet, a strain of music is sweet, and love is sweet, not 
to mention the saccharine reaction of the ' uses of adversity.' Here 
taste, smell, sight, hearing, and a social sentiment use the same word for 
that pleasurable sensation experienced by the mind through each distinc- 
tive organ. We assist the organ of one sense by that of another. We 
open the lips and part the teeth a little when we are eager to hear ; we 
listen and turn the eyes' attention inward when we would detect a deli- 
cate taste, or remember a faded impression. 

" But this mutual accommodation of the senses is not so marvelous as 
it may seem, when we remember that the whole five, six, or seven, as you 
please, are but one power of nervous perception, specialized into a variety 
of functions, differentiated, as the learned say, that we may have more 
perfect work by a division of labor. The same necessity which developed 
nerve-contact into sight on the one hand and hearing on the other might 
also express through one of these the sensations proper to the other, when 
the other was wanting. Seal up the eyes of a bat, say the naturalists, 
and let it loose in a room crossed with wires in every direction, and he 
will fly clear of them all, as if he had other means of perception as 
sensitive as the optic nerve. 

" Laura Bridgman, with neither sight, hearing, nor smell, could detect 
the presence of a stranger in the room, without contact. Her mind then 
must have as distinct an image of every person as we have, yet not one 
of what we call our senses could go to the making up of that image. It 
could not be form as we know it, nor a voice, nor an odor, but it was 
itself other than all, exciting emotions of love, or hate, gratitude or 
repugnance, and the thought it excited must have had shape, though it 
is not easy to imagine how." — The Schoolmaster. 



16. What are the special senses ? Special organs for them ? 



THE SPECIAL SENSES 271 

of special sense terminate varies in the case of each organ, so 
that each is adapted to one set of sensations alone, and is 
incapable of perceiving any other. Thus the nerve of hearing 
is excited by the waves of sound, and not by those of light, 
while the reverse is true of the nerve of sight ; and the nerve 
of smell can appreciate neither of them, being capable only 
of taking cognizance of the odorous properties of bodies. 
{Bead Note 3.) 

17. By some writers six senses are accorded to man, the 
additional one being either the sense of temperature — for, as 
we shall presently see, this is not the same as touch — or, 
according to others, the muscular sense by which we are 
enabled to estimate the weights of bodies. The latter also 
differs in some respects from the sense of touch. 

18. Organs of Touch. — The sense of touch is possessed by 
nearly all portions of the general surface of the body, but it 
finds its highest development in the hands. The human hand 
is properly regarded as the model organ of touch. The minute 
structure of the skin fits it admirably for this form of sensa- 
tion; the cuticle, or scarf-skin, is fine and flexible, while the 
cutis, or true-skin, contains multitudes of nerve-filaments, 
arranged in rows of papillae or cone-like projections, about one 
one-hundredth of an inch in length. It is estimated that there 
are 20,000 of these papillae in a square-inch of the palmar sur- 
face of the hand. Now, although the nerves of the cutis are 
the instruments by -which impressions are received and trans- 
mitted to the brain, yet the cuticle is essential to the sensation 
of touch. This is shown by the fact that whenever the true- 
skin is laid bare, as by a burn or blister, the o\\\j feeling that 
it experiences from contact is one of pain, not that of touch. 

3. Variation in Structure in the Nerves of Special Sense. — " While 
in the more intellectual Senses — Sight, Hearing, and Touch — the nerves 
have their protecting and isolating sheaths corresponding with the dis- 
tinctness and separateness of the parts of the impression, in Smell the 
nerves are a plexus of unsheathed fibres, corresponding with the fusion of 
the odorous impression into one whole, without distinction of parts." — 
Herbert Spencer. 

17. What is said in relation to one more than the the senses J 

18. The sense of touch, how prevalent ? What is said of the hand? 



272 THE SPECIAL SENSES 

19. The office of the cuticle is thus made evident; it is to 
shield the nerve-filaments from direct contact with external ob- 
jects. At the tips of the fingers, where touch is most delicate, 
the skin rests upon a cushion of elastic material, and receives 
firmness and permanence of shape by means of the nail placed 
upon the less sensitive side. Besides these favorable condi- 
tions, the form of the arm is such, and its motions are so easy 
and varied, that we are able to apply the test of touch in a great 
number of directions. The slender, tapering fingers, with their 
pliant joints, together with the strong opposing thumb, enable 
the hand to grasp a great variety of objects ; so that, great as 
are the delicacy and grace of the hand, it is not wanting in the 
elements of power. 

20. Its beauty and adaptation to the wants of man have made 
the hand an attractive theme for philosophers. They do not, 
however, always agree in their conclusions. One has the opin- 
ion that man has acquired his intelligence and achieved his 
place as " lord of creation," because he has this organ. Buffon, 
in effect, declares that with fingers twice as numerous, and twice 
as long, we would become proportionally wiser ; but Galen long 
ago took a more reasonable view, when he taught that " man 
is the wisest of animals, not because he possesses the hand, but 
because he is the wisest, and understands its use ; for his mind, 
not his hand, has taught him the arts." Another has well said, 
that " no one can study carefully the human hand and fail to be 
convinced of the existence of the Deity." 

21. The Sense of Touch. — Touch is the simplest of the senses. 
It is that which the child first calls into exercise in solving the 
early problems of existence, and it is that which is in the most 
constant use throughout life. We are brought by the touch 
into the most intimate relations with external objects, and by 
it we learn the greater number, if not the most important, of the 
properties of these objects, such as size, figure, solidity, motion, 
and smoothness or roughness of surface. 



19. Office of the cuticle ? Tips of the fingers ? The fingers with thumb ? 

20. What special importance is attributed to the hand ? 

21. The simplicity of touch ? What does it teach us ? 



THE SPECIAL SENSES 273 

22. The sense of touch, assists the other senses, especially 
that of sight, giving foundation and reality to their perceptions. 
Without it, the impressions received by the eye would be as 
vague and unreal as the figures that float through our dreams. 
A boy who had been blind from birth, at the age of twelve 
years received sight by means of a surgical operation ; at first, 
he was unable to distinguish between a globe and a circular 
card of the same color before he had touched them. After 
that, he at once recognized the difference in their form. He 
knew the peculiarities of a dog and a cat by feeling, but not 
by sight, until one day, happening to take up the cat, he recog- 
nized the connection of the two sorts of impressions — those of 
touch and sight; and then, putting the cat down, he said: 
" So, Puss, I shall know you next time." 

23. Of all the senses, touch is considered the least liable to 
error; yet, if that part of the skin by which the sense is 
exercised is removed from its customary position, a false 
impression may be created in the mind. This is well illus- 
trated by an experiment, which dates from the time of Aris- 




Fig. 61 

totle. If we cross the middle finger behind the forefinger, 
and then roll a marble or some small object upon the tips of 
the fingers (see Fig. 61), the impression will be that two mar- 
bles are felt. If the fingers, thus transposed, be applied to 
the end of the tongue, two tongues will be felt. When the 
nose is accidentally destroyed, the surgeon sometimes performs 

22. Importance of the sense of touch to the development of the other senses ! 

23. Liability of touch to err ? Describe the illustration. 



274 THE SPECIAL SEXSES 

an operation for the purpose of forming a new one, by trans- 
planting a partially removed piece of the skin of the forehead 
upon the injured part; then, if the new nose be touched or 
pinched, the feeling is referred to the forehead. This fact 
illustrates one important truth — that the nerves will re-unite 
after they have been cut and feeling will be restored; if it 
were otherwise, a succession of slight cuts upon the fingers 
would seriously impair their tactile sensibility. 

24. The Delicacy of Touch. — Although the hand is the 
proper organ of this sense, yet it is exercised by various parts 
of the body, their degree of sensibility being proportional to 
the number of papillae they contain. The varying degrees of 
tactile delicacy of the different parts of the surface have been 
measured in an ingenious manner, by means of a pair of com- 
passes, tipped with small pieces of cork. The two points of 
the compasses are touched at the same moment to the skin, the 
eyes being closed, and it is found that, in sensitive parts, the 
distance between the points may be "quite slight, and yet each 
be plainly felt ; while, in less sensitive parts, the points of the 
compasses are felt as a single point, although they are sepa- 
rated one or two inches. 

25. At the tips of the fingers, the distance between the 
points being one-twentieth of an inch, a double impression is 
felt. The distance must be twice as great for the palm, four 
times as great for the lips, and, on the forehead, it must be 
twenty times greater. At the middle of the back, where the 
touch is least acute, the points must be separated more than 
two inches before they can be separately felt. Therefore, the 
sense of touch in the fingers is said to be fifty times more 
delicate than upon the posterior surface of the body. 

26. Exquisite delicacy of touch is attained by practice. 
This is shown in many of the lighter and more graceful 
employments of daily life. Without it, the skill of the 
painter, sculptor, and musician would be rude indeed. By 

24. The delicacy of touch ? Experiments with a pair of compasses ? 

25. Further experiments and results ? 

26. Exquisite delicacy of touch ? The same among the blind ? 



THE SPECIAL SENSES 275 

training, also, the physician acquires the tactus eruditus, or 
discriminating touch ; but among the blind, delicacy of touch 
is most remarkable, and it there finds its highest value; for 
its possession, in a measure, compensates for the loss of sight 
by enabling them to read, by means of raised letters, to work 
with certain tools, and even to play upon musical instruments. 
A person born without sight, and without hearing or voice, 
may, by the education of the touch, be rescued from apparent 
imbecility, and be taught not only to read and write, but even 
to perform household and other useful labors. 

27. Sensations of Temperature and Weight. — Each of these 
sensations has been described by the physiologists as a special 
sense, and they are rival candidates, so to speak, for the posi- 
tion and title of the sixth sense. In the sensation of temper- 
ature, or the thermal sense, touch bears a part, but the two 
feelings appear to be distinct. In proof of this, we observe, 
firstly, that they are not alike intense in the same situations ; 
as, for example, the skin of the face and elbow, where the 
sense of touch is feeble, is very sensitive to impressions of 
heat and cold. Secondly, the ability to recognize temperature 
may be lost by paralysis, while the sensibility of touch remains 
unaffected. When the skin comes in contact with a very hot 
substance, the sensation felt is that of pain — not of touch. 
In like manner, a very cold substance causes pain, not the 
feeling of cold. So that a red-hot iron, and solid carbonic acid 
(the temperature of which is 108° below zero), feel alike ; and 
each, if pressed slightly, will produce a blister. (Bead Note 4.) 

4. Qualities Determined by the Sense of Touch. — "The eye, by 
the aid of certain signs, is often able to tell whether a body is hot — 
when, for instance, it is glowing or steaming — but a perception of 
warmth is not possessed by the eye. This is had by the skin alone, 
and it is of great importance to our preservation that this property is 
spread over the entire surface ; for it surrounds the body like a pro- 
tecting wall against its worst enemy — cold — which, if not thus guarded 
against at all points, would speedily destroy life. We are warned, how- 
ever, of the approach of the enemy by a common sensation of the 
skin, and an inward chill, which is only caused by a coolness of the 



27. Rival candidates for the sixth sense ? Give the two reasons on the subject. 



276 THE SPECIAL SENSES 

28. The muscular sense, by some considered distinct from 
touch, gives rise to the sensations of weight, and other forms 
of external resistance. That this feeling exists, is shown by 
the following simple experiment : if the hand be placed flat 
upon a table, and a somewhat heavy weight be put into it, 
touch alone is exercised, and a feeling of pressure results; but 
if the hand be raised, a certain amount of muscular effort must 
be put forth, and thus the sensation of weight is recognized. 
Through the muscular sense, precision of effort is rendered pos- 
sible ; for by it we learn to adjust the force exerted to the 
weight of the object to be lifted, moved, or carried. Without 
it all our movements would necessarily become ill-regulated 
and spasmodic. In cases of disease, where the sensibility of 
the lower limbs is lost while power of motion remains, the 
patient is able to stand erect so long as he can see his limbs ; 
but just as soon as his eyes are closed, he begins to waver, and 
will fall unless supported. 

29. The Organ of Taste. — The tongue is the special organ 
of the sense of taste ; but the back part of the mouth always 
possesses this faculty. The tongue is a muscular organ, the 

skin. The skin, in like manner, protects the body against the approach 
of a hurtful degree of heat. Thus, you see, the skin has certain quali- 
ties of sensation. Just as the eye, in looking at a wafer, perceives 
that it is both red and circular, distinguishing both the color and form 
of bodies, so the sensitive skin by contact with an object distinguishes 
the qualities of form, firmness, hardness, liquidity, pressure, and tempera- 
ture. * * * Weber has discovered the interesting fact that warm 
bodies feel lighter than cold ones : if a cold coin be placed upon the 
forehead of some person, whose eyes are shut, and then upon the same 
spot two warm coins, the weight would seem to him the same, whilst 
he could distinguish correetly in the case of cold weights. * * * If 
we place the elbow in hot water, we experience heat only in the part 
immersed, not in the whole arm, although the nerve just under the skin 
runs throughout the arm and hand. What we feel is a dull sense of 
pain in the whole arm if the water is too hot. So, too, if the elbow 
is placed in ice- water the pain is just the same in the arm ; proving 
that the nerve trunk can feel neither warmth nor cold." — Bernstein's 
Five Senses of Man. 

28. The muscular sense? State what is said to illustrate the subject. 
29; The organ of taste ?• The. tongue ? Its powers of motion ?■ 



THE SPECIAL SENSES 211 

muscles composing it being so numerous and interwoven as to 
give it the freedom and variety of motion which it possesses. 
It can curve itself upward or downward ; it can extend or con- 
tract itself ; and, with its point, can sweep the cavity of the 
mouth, in all directions, in the search for scattered particles of 
food. 

30. The upper surface of the tongue is peculiar, being 
marked by the presence of innumerable papillae, some of which 
are of microscopic size, resembling those that abound in the 
fingers, and in other parts of the body that have the sense of 
touch. Others are much larger, and give to the tongue its 
roughness of feeling and appearance. Through the medium 
of these papillae, the tongue receives impressions of touch and 
temperature, as well as taste : indeed, its extremity is fully as 
delicate, in respect to tactile sensations, as the -tips of the fin- 
gers themselves. It can recognize the two points of the com- 
passes when separated not more than one^ twenty-fourth of an 
inch ; the back of it is much less sensitive to touch, while at 
the same time it is more highly sensitive to impression of 
taste. 

31. Each lateral half of the tongue resembles the other in 
structure, and each receives the same number of nerves — 
three. One of these regulates motion, the other two are nerves 
of special sense. One of the latter supplies the front half 
of the tongue, and is called the gustatory nerve. This is a 
branch of the great cranial nerve, called the "fifth pair," which 
ramifies in all parts of the face. The back of the tongue is 
endowed with the power of taste, through a nerve known as 
the glosso-pharyngeal, because it is distributed both to the 
tongue and throat. This difference in the nervous supply of 
the tongue becomes significant, when we learn, as we shall 
presently, that each part of it perceives a different class of 
flavors. 

32. The Sense of Taste. — Taste is the special sense by means 

30. Peculiarities of the tongue ? Uses of the papilla* ? 

31. Resemblance in the parts of the tongue? Cowers and fuiu'tions of the parts? 
82. Taste ? What are the requisites to taste ? 



278 THE SPECIAL SENSES 

of which we discover the savors, or flavoring properties of the 
substances which come in contact with the tongue. Mere con- 
tact with the surface of the tongue, however, is not sufficient, 
but contact with the extremities of the nerves of taste within 
the papillae is required. In order that the substance to be 
tasted may penetrate the cells covering the nerves, it must 
either be liquid in form, or readily soluble in the watery secre- 
tion of the mouth — the saliva. The tongue must be moist 
also. If the substance be insoluble — as glass or sand — or 
the tongue dry, the sense of taste is not awakened. In sick- 
ness, when the tongue is heavily coated, the taste is very defec- 
tive, or, as is frequently said, " nothing tastes aright." 

33. All portions of the tongue are not alike endowed with 
the sense of taste, that function being limited to the posterior 
third, and to the margin and tip of this organ. The soft pal- 
ate, also, possesses the sense of taste; hence, an article that 
has an agreeable flavor may very properly be spoken of as pal- 
atable, as is often done. All parts of the tongue do not per- 
ceive equally well the same flavors. Thus, the front extremity 
and margin, which is the portion supplied by the " fifth pair " 
of nerves, perceives more acutely sweet and sour tastes; but 
the base of the tongue, supplied by the glosso-pliaryngeal nerve, 
is especially sensitive to salt and bitter substances. The nerve 
of the front part of the tongue, as before stated, is in active 
sympathy with those of the face, while the relations of the 
other nerve are chiefly with the throat and stomach ; so that 
when an intensely sour taste is perceived, the countenance is 
involuntarily distorted, and is said to wear an acid expression. 
On the other hand, a very bitter taste affects certain internal 
organs, and occasions a sensation of nausea, or sickness of the 
stomach. {Bead Note 5. ) 

5. Flavors and Sense of Taste. — "The cause and intimate nature 
of tastes are no better understood than those of odors. Flavors elude 
analysis and defy classification, even that which divides them into agree- 
able and disagreeable, for the taste of individuals and of nations singu- 
larly differs in this respect. The Laplander and the Esquimau drink 



33. Portions of the tongue endowed with taste ? Where else does the sense lodge ? 
What is stated in respect to sweet and bitter flavors ? Keflex effects mentioned ? 



THE SPECIAL SENSES 279 

34. Relations of Taste with other Senses. — Taste is not a 
simple sense. Certain other sensations, as those of touch, tem- 
perature, smell, and pain, are blended and confused with it; 
and certain so-called tastes are really sensations of another 
kind. Thus an astringent taste, like that of alum, is more 
properly an astringent feeling, and results from an impression 
made upon the nerves of touch that ramify in the tongue. In 
like manner, the qualities known as smooth, oily, watery, and 
mealy tastes, are dependent upon these same nerves of touch. 
A burning or pungent taste is a sensation of pain, having its 
seat in the tongue and throat. A cooling taste, like that of 
mint, pertains to that modification of touch called the sense of 
temperature. 

35. Taste is largely dependent upon the sense of smell. A 
considerable number of substances, like vanilla, coffee, and gar- 
lic, which appear to possess a strong and distinct flavor, have 
in reality a powerful odor, but only a feeble taste. When the 
sense of smell is interfered with by holding the nose, it becomes 
difficult to distinguish between substances of this class. The 

great quantities of train-oil, which for them is a greatly-esteemed 
article of food, and is most admirably adapted to the exigencies of a 
Polar climate ; the Abyssinians eat raw flesh, and find its flavor 
excellent, while the inhabitant of the West partakes of it with the 
greatest repugnance and only as a medicine. Oysters, which are so 
generally esteemed in our country, are to some persons disagreeable 
and nauseous ; and truffles, the delight of the gourmand, are rejected 
by the uninitiated on account of their flavor and their perfume. It is 
the same with almost all alimentary substances ; they are eagerly 
sought after by some, and despised or abhorred by others. Let us 
remember the proverb ' de gustibus non dispntandum,' 1 and not dispute 
in regard to tastes ; each is suited to its own country, and goodly 
numbers acclimatize themselves, to the great advantage of peoples 
among whom at first they seem exceedingly strange. Man should 
control his taste, and habituate it to all wholesome aliment ; this 
neither excludes choice, nor blunts the delicacy of the sense ; and 
while we resist its seductions, we should give timely heed to its 
instincts and its counsels, for they are often invaluable. 1 ' — The Won- 
ders of the Human Body. 



34. What is stated of the relations of taste to the other senses } 

35. Its dependence on smell ? on sight ? 



280 THE SPECIAL SENSES 

same effect is frequently observed when smell is blunted during 
an ordinary cold in the head. Sight also contributes to taste. 
With the eyes closed, food appears comparatively insipid; and 
a person smoking tobacco in the dark is unable to determine by 
the taste whether his cigar is lighted or not. Accordingly, it 
is not a bad plan to close the nose and shut the eyes when 
about to swallow some disagreeable medicine. 

36. Influence of Education on the Taste. — The chief use of 
the sense of taste appears to be to act as a guide in the 
selection of proper food. Hence its organs are properly placed 
at the entrance of the digestive canal. As a general rule, 
those articles which gratify the taste are wholesome ; while the 
opposite is true of those which impress it disagreeably. This 
statement is more exact in reference to the early than to the 
later years of life, when, by reason of improper indulgence, the 
sense of taste has become dulled or perverted. The desires of 
a child are simple ; he is fully satisfied with plain and whole- 
some articles of diet, and must usually "learn to like" those 
which have a strongly marked flavor. Accordingly, it is far 
easier at this age to encourage the preference for plain food, 
and thus establish healthful habits, than later in life to uproot 
habits of indulgence in stimulating substances, after their ill 
effects begin to manifest themselves. 

37. The tastes of men present the most singular diversities, 
partly the result of necessity and partly of habit or education. 
The Esquimaux like the rank smell of whale-oil, which is a 
kind of food admirably suited to the requirements of their icy 
climate ; and travelers who go from our climate to theirs are 
not slow to develop a liking for the same articles that the 
natives themselves enjoy. The sense of taste is rendered very 
acute by education, as is shown in an especial manner by those 
who become professional "tasters" of tea and wine. 

38. The Sense of Smell — the Nasal Cavities. — The sense of 
smell is located in the delicate mucous membrane which lines 

36. The chief use of the sense oi taste ? The position of the organs? The rule as 
regards wholesome and unwholesome food ? Eemarks respecting the rule ? 

37. Diversity in tastes of men ? How shown ? The education of the sense of taste ? 

38. Location of the sense of smell ? The nose ? " Eoof of the mouth ? " 



THE SPECIAL SENSES 281 

the interior of the nose. That prominent feature of the face, 
the nose, which is merely the front boundary of the true nasal 
organ, is composed partly of bone and partly of cartilage. The 
upper part of it is united with the skull by means of a few 
small bones, to which circumstance is due its permanence of 
shape. The lower portion, or tip of the nose, contains several 
thin pieces of cartilage, which render it flexible and better able 
to resist the' effects of blows and pressure. Behind the nose we 
find quite a spacious chamber, separated from the mouth by 
the hard palate, forming the " roof of the mouth," and also by 
the soft palate (see Fig. 62) ; and divided into two cavities by a 
central partition running from before backward. 

39. These nasal cavities, constituting the true beginning of 
the air-passages, extend from the nose backward to the upper 
opening of the throat, and rise as high as the junction of the 
nose with the forehead. The inner wall of each cavity is 
straight and smooth ; but from the outer wall there jut into 
each cavity three small scroll-like bones. The structure of 
these bones is very light, and hence they have been called the 
" spongy " bones of the nose. In this manner, while the extent 
of surface is greatly increased by the formation of these wind- 
ing passages, the cavities are rendered extremely narrow; so 
much so, in fact, that a moderate swelling of the mucous mem- 
brane which lines them, as from a cold, is sufficient to obstruct 
the passage of air through them. 

40. The Nerve of Smell. — The internal surface of the nasal 
passages is covered by a delicate and sensitive mucous mem- 
brane. Its surface is quite extensive, following as it does all 
the inequalities produced by the curved spongy bones of the 
nose. Only the upper portion of it is the seat of smell, since 
that part alone receives branches from the "first pair" o\' 
cranial nerves, or the olfactory nerve, which is the special 
nerve of smell (see Fig. 62). In Fig. 62 is shown the distribu- 
tion of this nerve, in the form of an intricate network upon the 
two upper spongy bones. The nerve itself (\) doc* not issue 



:;;>. Cavities of the nose ? Obstruction of the passage o\' air through them v 
40. The special nerve of smell ? Its location ? 



282 



THE SPECIAL SENSES 



from the skull, but rests upon a thin bone which separates 
it from the cavity of the nose ; and the branches which proceed 
from it pass through this bone by means of numerous small 
openings. The engraving represents the outer surface of the 
right nasal cavity ; the three wave-like inequalities, upon which 
the nervous network is spread out, are due to the spongy bones. 
The left cavity is supplied in the same manner. 

41. The nerves which ramify over the lower part of the 
membrane, and which endow it with sensibility to touch and 
pain, are branches of the 
" fifth pair" of nerves. 
An irritation applied to 
the parts where this nerve 
is distributed occasions 
sneezing — that is, a spas- 
modic contraction of the 
diaphragm, the object of 
which is the expulsion of 
the irritating cause. The 
manner in which the ol- 
factory nerve-fibres termi- FlG - 62 " ~ Section of the Right Na8al Cavitt 
nate is peculiar. Unlike the extremities of other nerves, which 
are enclosed by a greater or less thickness of tissue, these come 
directly to the surface of the mucous membrane, and thus are 
in very close contact with the odorous particles that are carried 
along by the respired air. The surface is at all times kept in 
a moist condition by an abundant flow of nasal mucus ; other- 
wise it would become dry, hard, and insensitive from the con- 
tinual passage of air to and fro in breathing. Birds, which 
respire more actively than men, have a special gland for secret- 
ing a lubricating fluid, located in the air-passages of the head. 

42. The Uses of the Sense of Smell. — Smell is the special 
sense which enables us to appreciate odors. Touch, as we have 
seen, is largely concerned with solid bodies, and taste with 




41. Branches of the " fifth pair " of nerves ? Nasal mucus ? Birds ? 

42. Smell ? Touch ? Taste ? Design of smell ? Invisible and gaseous particles ? The 
extreme fineness of the particles ? Musk ? In other cases ? 



THE SPECIAL SENSES 283 

fluids, or with solids in solution. Smell, on the other hand, is 
designed to afford us information in reference to substances 
in a volatile or gaseous form. Invisible particles issue from 
odorous bodies and are brought by the respired air in contact 
with the terminal filaments of the olfactory nerve, upon which 
an agreeable or disagreeable impression is produced. The fine- 
ness of the particles that constitute odors is often so extreme 
that they elude all attempts to measure or weigh them. A 
piece of musk, for instance, may be kept for several years, 
constantly emitting perfume without any appreciable loss of 
weight. In other cases, a loss of substance is perceptible, as 
in the essential oils, which enter into the composition of the 
ordinary perfumes. 

43. Smell, like taste, aids us in the choice of proper food, 
leading us to reject such articles as have a rank or putrid odor, 
and which are, as a rule, unfit to be eaten. The highest use- 
fulness of this sense, however, consists in the protection it 
affords to the organs of respiration. Stationed at the gateways 
of the air-passages, it examines the current of air as it enters, 
and warns us of the presence of noxious gases, and of other and 
generally invisible enemies to health. Not all dangerous vapors 
are offensive, but almost all offensive vapors are unfit to be 
breathed. A number of small stiff hairs grow from the margin 
of the nostrils to prevent the entrance of dust and other atmos- 
pheric impurities, which would be alike injurious to the olfac- 
tory mucous membrane and to the lungs. The benevolent 
design of the Maker of our bodies may be observed in all parts 
of their mechanism; but, probably, in none is it more clearly 
displayed than in connection with the sense of smell. {Read 
Note 6.) 

6. The Protective Function of the Sense of Smell. — " Smell seems 

to be regarded as an endowment bestowed simply for pleasure, serving to 
promote no important or vital end. That its main use is to signal danger 
to internal parts is not duly appreciated. The detection of an offensive 
odor is thought to be the only bad thing about it, and which, to those 
habituated to it, is of no subsequent importance. Men even pride them- 
selves on becoming accustomed to offensive odors, and quite enjoy the 



48. Aid given by smell ? The highest use of the sense ? Kxplatu the manner. 



284 THE SPECIAL SENSES 

44. The sense of smell is developed in a remarkable degree 
in certain of the inferior animals, and is especially acute in 
reference to the peculiar odors that characterize the different 
animals. The lion and other carnivorous beasts scent their 
prey from a great distance ; and the fox-hound is able to track 
the fox through thickets and over open country for many miles ; 
while the timid, helpless herbivora, such as the deer and sheep, 
find in the sense of smell a means of protection against their 
natural enemies, of whose approach they are in this manner 
warned. By training this sense in the dog, and making it sub- 
servient to his use, man is able to hunt with success certain shy 
and very fleet animals, which otherwise he could but seldom 
approach. Among men, individuals differ greatly in respect to 
the development of this sense ; and especially in certain savage 
tribes it is found to be extremely delicate. Humboldt states 
that the natives of Peru can by it distinguish in the dark 
between persons of different races. {Read Note 7.) 

sight of one whose nerve of smell is not benumbed like their own. In- 
stead of seeking to blunt the sensibilities of this nerve, it should be a 
study to improve it, as the most delicate and available test of air im- 
purity — far superior, under ordinary circumstances, to the tests of 
science. In this way all ordinary atmospheric impurities may be quickly 
detected ; and it is truly remarkable how, by a little attention, this sense 
can be so improved as to detect instantly even slight impurities to 
which it had before been insensible. In many houses, by the total 
neglect of this sense, there is an ever-present family odor, produced by 
some special kind of household impurity, and of which the inmates do 
not seem to be aware. To those accustomed to pure air, house odors are 
always perceptible and disagreeable. This ought to be accepted as suffi- 
cient evidence of their unhealthful tendencies ; not perhaps of an instant 
or violent sort, yet enough so to give rise to many sensations of slight dis- 
comfort, and producing, when long continued, a state of the body very 
favorable to the beginning and growth of virulent diseases." — Black's 
Ten Laws of Health. 

7. The Effects of Certain Odors. — "I have not seen it anywhere laid 
down as a general rule, but I believe it might be affirmed, that we are 
intended to be impressed only sparingly and transiently by odor. There 
is a provision for this in the fact that all odors are vapors or gases, or 
otherwise volatile substances ; so that they touch but the inside of the 
nostril, and then pass away. 



44. Sense of smell in inferior animals f How, and in what cases illustrated ? 



THE SPECIAL SENSES 285 

45. The Sense of Sight. — Sight, or vision, is the special 
sense by means of which we appreciate the color, form, size, 
distance, and other physical properties of the objects of exter- 
nal nature. Primarily, this sense furnishes us with informa- 
tion concerning the different shades of color and the different 
degrees of brightness : these are the simple sensations of sight, 
such as the yellowness and glitter of a gold coin. In addition 
to these, there are composite visual sensations, produced by the 
joint action of the other senses and by the use of the memory 
and judgment ; such as, in the case of the coin, its roundness, 
solidity, size, its distance and direction from us. So that many 
of our sensations, commonly considered as due to sight, are in 
reality the results of intellectual processes which take place 
instantaneously and unconsciously. 

46. This faculty not only is valuable in the practical every- 
day affairs of life, but it contributes so largely to the culture 
of the intellect and to our higher forms of pleasure, that some 
writers are disposed to rate it as the first and most valuable of 
the senses. Others, however, maintain that the sense of hear- 
ing does not yield in importance to that of sight ; and they cite 

"In conformity with this fleeting character of odorous bodies, it is a 
law in reference to ourselves, to which, as far as I know, there is no 
exception, that there is not any substance having a powerful smell of 
which it is safe to take much internally. The most familiar poisonous 
vegetables, such as the poppy, hemlock, henbane, monk's-hood, and the 
plants containing prussic acid, have all a strong and peculiar smell. 
Nitric, muriatic, acetic, and other corrosive acids, have characteristic 
potent odors, and all are poisons. Even bodies with agreeable odors, 
like oil of roses, or cinnamon, or lavender, are wholesome only in very 
small quantities, and, when the odor is repulsive, only in the smallest 
quantities. So far as health is concerned, the nostril should be but 
sparingly gratified with pleasing odors or distressed by ungrateful ones. 
No greater mistake can be made in sick-rooms than dealing largely in 
aromatic vinegar, eau de cologne, lavender water, and other perfumes 
This hiding of one odor by another is like trying to put away the taste of 
bitter aloes by that of Epsom salts. Physical comfort is best secured by 
rarely permitting an infraction of the rule that the condition of health is 
no odor at all." — Wilson on the Five Gateways of Knowledge. 



45. Whatis sight? What information does it furnish? Composite' visual setfsations J 

46. Comparison between si<rht and hearing ? Relative capaoity of deaf" and blind ? 



286 THE SPECIAL SENSES 

in support of their position the fact that the blind are com- 
monly cheerful and gay, while the deaf are inclined to be 
morose and melancholy. In respect to the relative capacity 
for receiving education in the deaf and blind, it is found that 
the former learn more quickly, but their attainments are not 
profound ; while the blind acquire more slowly, but are able 
to study more thoroughly. 

47. Light — The Optic Nerve. — Unlike the senses previously 
considered — touch, taste, and smell — sight does not bring us 
into immediate contact with the bodies that are examined ; but, 
by it, we perceive the existence and qualities of objects that are 
at a greater or less distance from us. In the case of the stars, 
the distance is incalculable, while the book we read is removed 
but a few inches. Light is the agent which gives to this sense 
its wide range. The nature of this mysterious force is not 
known, and it is not here to be discussed, since its study 
belongs more properly to the province of natural philosophy. 

48. It is sufficient, in this connection, to state that the theory 
of light now generally accepted, and which best explains the 
facts of optics, is that known as the undulatory theory. This 
theory supposes that there exists an intangible, elastic medium, 
which fills all space, and penetrates all transparent substances, 
and which is thrown into exceedingly rapid undulations or 
waves, by the sun and every other luminous body — the undu- 
lations being propagated with extreme rapidity, and moving 
not less than 186,000 miles in a second. 

49. These waves are thought to produce in the eye the sen- 
sation of light, in the same manner as the sonorous vibrations 
of the air produce in the ear the sensation of sound. That 
part of the eye which is sensitive to these waves is the expan- 
sion of the optic nerve. It is sensitive to no other impression 
than that of light, and it is the only nerve which is acted upon 
by this agent. The optic nerve, also called the " second pair " 
of cranial nerves, is the means of communication between the 
eye and the brain. 

47. Sight unlike the other senses ? In the case of the stars ? 

48. The undulatory theory of light ? What does the theory suppose ? 

49. The sensation of light ? Optic nerve ? 



THE SPECIAL SENSES 287 

50. The two nerves constituting the pair arise from ganglia 
lying at the base of the cerebrum — one of them on each side 
— from which points they advance to the eyes, being united 
together in the middle of their course in the form of the letter 
X (Fig. 57, 2). By this union the two eyes are enabled to act 
harmoniously, and in some respects to serve as a double organ. 
By-reason of this same intimate nervous communication, when 
serious disease affects one eye, the fellow-eye is extremely 
liable to become the seat of sympathetic inflammation ; and this, 
if neglected, almost certainly results in hopeless blindness. 

51. The Organ of Sight — The Eye. — The proximity of the 
eye to the brain, and the important part it performs in giving 
expression to the emotions, have given it the name of "the 
window of the soul." The exceeding beauty of its external 
parts, and the high value of its function, have long made this 
organ the subject of enthusiastic study. It is chiefly within 
the last twenty years, however, that this study has been suc- 
cessful and fruitful of practical results. Several ingenious 
instruments have been invented for the examination of the eye 
in health and disease, and new operations have been devised 
for the relief of blindness and of impaired vision. As a result, 
it is now a well-marked fact that, in civilized lands, the num- 
ber of those who suffer from loss of sight is proportionally 
much less than in countries where science is less known and 
cultivated. 

52. The most obvious fact in respect to the apparatus of 
sight is that there are two eyes, which may either act together 
as one, and be fixed upon one object, or one eye may be used 
independently of the other. In consequence of this arrange- 
ment, the loss of one eye does not necessitate blindness, and, 
in fact, it not infrequently happens that the sight of one eye 
may be long impaired or lost before the fact is discovered. 
We next notice that the eyes are placed at the most elevated 



50. Tho two nerves constituting the pair of nerves ? 

51. Why is the eye called " the window of the soul " F Why the subject of enthusiastic 
study ? 

52. The most obvious fact ? The consequence f The next thing noticed ( Its range of 
View ? Of what does the organ of vision consist ? 



288 THE SPECIAL SENSES 

part of the body, in front, and near the brain. They also com- 
mand a wide range of view, being moved with great rapidity, 
and being further aided by the free motion of the head and 
neck. The organ of vision consists essentially of two parts : 
the optical instrument itself — the eyeball — and its envelop- 
ing parts, or the case in which the instrument is kept free from 
harm. The latter, which are external, and which we shall first 
consider, are chiefly the orbits, the eyelids, and the apparatus 
for the tears. 

53. The Orbits. — The eyeball, which is a delicate organ, is 
well defended against external injury within the orbits or bony 
sockets of the head. These are deep conical hollows, bounded 
in part by the bones of the skull, and in part by those of the 
nose and cheek. The orbit juts out beyond the most exposed 
portion of the eyeball, as may be seen by laying a book over 
the eye, when it will be found that no part of the eyeball, 
unless it be very prominent, will be touched by the book ; so 
that the only direction in which an injury is liable to be 
received is immediately in front of the eye. The overhanging 
brow is itself covered by a layer of thick skin, studded with 
short, stout hairs, which are so bent as to prevent the perspira- 
tion from running into the eye and obscuring" vision. Through 
a hole in the bottom of the orbit, the nerve of sight passes out- 
ward from the brain. The orbit also contains a considerable 
amount of a fatty tissue, upon which, as upon an elastic 
cushion, the eye rests. 

54. The Eyelids. — The eyelids are two movable curtains, or 
folds, which, when shut, cover the front part of the orbit, and 
hide the eye from view. The upper lid is the larger, has a 
curved margin, and moves freely, while the lower lid is com- 
paratively short and straight, and has but a slight degree of 
motion (Fig. 63). Skin covers the exterior of the lids, while a 
fine mucous membrane lines their inner surface, and is likewise 
spread out over the entire front of the eyeball. This membrane, 

53. The protection of the eyeball against injury ? The overhanging brow ? The opening 
for the optic nerve ? 

54. What are the eyelids ? The upper lid ? The lower one ? The mucous membrane of 
the eye ? 



THE SPECIAL SENSES 



289 




which is called the conjunctiva, is highly sensitive, and thus 
plays an important part in protecting the eye against the lodg- 
ment of sand, ashes, chaff, 
and other foreign particles 
that are blown about in the 
air. This sensitive mem- 
brane will not endure the 
presence of these particles. 
If any dust finds access, it 
causes a constant winking, 
a flow of tears, and other 
signs of irritation, until it 
is removed. (Bead Note 8. ) 

55. The long, silky eye- 
lashes, which garnish the 
edges of the lids, act like a 
sieve to prevent the entry of 
dust and other irritants ; and 
together with the lids, they 
regulate the amount of light which is permitted to enter the 
eye, so that it is shielded from a sudden flood or glare of light. 
The little points seen in the figure just within the line of the 
lashes, especially on the lower lid, represent the mouths of 
numerous little sebaceous glands (Fig. 64, d, d), such as are 
always found in the neighborhood of hairs. These glands sup- 
ply a thick, oily material which greases the edges of the lids 
and prevents their adhering together, and likewise prevents 
the overflow of the tears upon the cheek. 



Fig. 63. — Front View of Right Eye. 
(Natural Size) 

1. The Lachrymal, or tear gland, lying be- 
neath the upper eyelid 

2. The Nasal Duct is shown by the dotted 
line. The * marks the orifice in the lower lid 

The central black spot is the pupil; sur- 
rounding it is the iris; and the triangular 
white spaces are the visible portion of the 
sclerotic 



8. How to Remove Foreign Bodies from the Eye. — "Lay your 
ringer on the cheek, and draw the lower lid gently down, while the person 
looks as much upward as possible, and we shall see about the whole ex- 
tent of the lower portion of the conjunctiva, and thus, if any foreign 
substance is there, it will be readily detected, and easily wiped away with 
a folded soft rag or handkerchief. Both lids have a piece of cartilage in 
them to stiffen them, like pasteboard, and keep them fitting close to the 
eyeball. The upper portion of this conjunctival sac can only be seen by 
turning over the upper lid. The way to do this is to let the person look 



55. The eyelashes ? Tho little points within tho line of the lashos I Of what uso are 
these glands ? 



290 THE SPECIAL SENSES 

56. The Lachrymal Fluid, or the Tears. — Just within the 
outer part of the bony arch of the brow, where the bone may 
be felt to be sharper than in other positions, is lodged a little 
organ called the lachrymal gland, the situation of which is 
indicated in Fig. 63, 1. This is the gland whence flows the 
watery secretion, commonly called the tears, which is designed 
to perform an exceedingly important duty in lubricating the 
lids, and in keeping the exposed surface of the eyeball moist 
and transparent. For, without this or some similar liquid, the 
front of the eye would speedily become dry and lustreless, like 
that of a fish which has been removed from the water; the 
simple exposure of the eye to the air would then suffice to 
destroy vision. 

57. This secretion of the tears takes place at all times, 
during the night as well as the day ; but it is seldom noticed, 
unless when under the influence of some strong mental emo- 
tion — whether of sorrow or happiness — it is poured forth 
in excess, so as to overflow the lids. Strong light or a rapid 
breeze will, among many other causes, excite the flow of the 
tears. That portion of this secretion which is not used in 
moistening the eye is carried off into the nose by a canal situ- 
down with the eyes closed. Taking hold of the lashes with one hand, 
and applying a pencil, or some small, round, smooth object, over the lid 
above the globe, we lift the lashes out and up, warning the person to still 
keep looking down. The lid will suddenly turn over with a little spring 
from the bending of the cartilage. In this way nearly the whole of the 
conjunctival sac will be exposed, and any foreign body wiped away, as 
above described. But suppose no friend or oculist is by us to do this. 
The next best thing is to take hold of the lashes of the upper lid, and 
draw it forward and downward over the lower one, blowing the nose 
violently with the other hand at the same time. 

" If the foreign substance is on the cornea, take a strip of paper not 
stiffer than ordinary writing-paper, about a quarter of an inch wide, and 
roll it up as if you were going to make a candle -lighter. Look at the 
lower end, and you will see it comes to a point. With this point now you 
may safely attempt to remove any foreign substance from the cornea. 
The tears which will flow soften the paper, and prevent injury to the 
delicate covering membrane of the cornea." — Dr. B. Jay Jeffries. 



56. The location of the lachrymal gland ? The use of the gland ? 

57. When does the secretion of the tears occur ? The secretion not used for the eye ? 
Location of the nasal duct ? Its use ? The overflow of tears in old people ? 



THE SPECIAL SENSES 291 

ated near the inner angle of the eye, called the nasal duct. 
This duct is shown in Fig. 63, 2, and is connected with each 
lid by delicate tubes, which are indicated by dotted lines in 
the figure ; the asterisk marks the little opening in the lower 
lid, by which the tears enter the nasal duct. By gently turn- 
ing the inner part of that lid downward, and looking in a mir- 
ror, this small " lachrymal point " may be seen in your own 
eye. In old people, these points become turned outward, and 
do not conduct the tears to the nasal cavity, thus causing an 
overflow of tears upon the face 

58. Thus we observe that the gland which forms the tears 
is placed at the outer part of the eye, while their means of 
exit is at the inner angle of the eye; which fact renders it 
necessary that this watery fluid shall pass over the surface of 
the eyeball before it can escape. This arrangement cannot be 
accidental, but evinces design, as it thus secures the perfect 
lubrication of the surface of the eye, and cleanses it from the 
smaller particles of dust which may enter it, in spite of the 
vigilance of the lids and lashes. The act of winking, which 
is generally unconsciously performed, and which takes place 
six or more times in a minute, assists this passage of the tears 
across the eye, and is especially frequent when the secretion 
is most abundant. 

59. The Eyeball. — The eyeball, or globe of the eye, upon 
which sight depends, is, as the name indicates, spherical in 
shape. It is not a perfect sphere, since the front part projects 
somewhat beyond the rest, and at the posterior part the optic 
nerve (Fig. 64, n) is united to it, resembling the junction of 
the stem with the fruit. In its long diameter — that is, from 
side to side — it measures a little more than an inch; in other 
directions it is rather less than an inch. In structure the h&£! 
of the eye is firm, and its tense round contour may in part be 
felt by pressing the fingers over the closed lids. 

60. The eyeball is composed chiefly of three internal, trans- 
parent media, called humors, and three investing coats, or 

58. The waterj^fluid passing over the eyeball : ; Design of the arrangement ? Winking ? 

59. Describe the shape of the eyeball. Its structure. 

60. Of what is the eyeball composed ? State how. 



292 



THE SPECIAL SENSES 



tunics. The former are the aqueous humor, Fig. 64, a, the 
crystalline lens l, and the vitreous humor v. Of these the lens 
alone is solid. The three coats of the eyeball are called the 
sclerotic s, the choroid Ch, and the retina r. This arrangement 
exists in respect to five-sixths of the globe of the eye, but in 
the anterior one-sixth, these coats are replaced by the cornea c, 
which is thin and transparent, so that the rays of light pass 
freely through it, as through a clear window-pane. 

61. In shape, the cornea is circular and prominent, resem- 
bling a miniature watch-glass, about -^ of an inch thick. In 




Fig. 64. — Vertical Section of the Eye (Enlarged) 



C. The Cornea 

A, The Aqueous Humor 
I, The Iris 

P, The Pupil 

L, The Crystalline Lens 

H, The Ligament of the Lens 

B, The Ciliary Process 

V, The Cavity containing the Vitreous Humor 
S, The Sclerotic 



Ch, The Choroid 

E, The Eetina 

N, The Optic Nerve 

DD, The Eyelids 

X, The Levator Muscle of the Upper 

Lid 
T, The Upper Straight Muscle of the 

Eye 
Z. The Lower Straight Muscle 



structure, it resembles horn (as the name signifies), or the nail 
of the finger, and is destitute of blood-vessels. The sclerotic 



61. The shape of the cornea ? Its structure ? The " white of the eye " ? 



THE SPECIAL SENSES 293 

(from scleros, hard) is composed of dense, white fibrous tissue, 
and gives to the eyeball its firmness of figure and its white 
color ; in front, it constitutes the part commonly called " the 
white of the eye." It is one of the strongest tissues in the 
body. It possesses very few vessels, and is not very sensitive. 
It affords protection to the extremely delicate interior parts 
of the eye, and the little muscles which effect its movements 
are inserted into the sclerotic a short distance behind the 
cornea (see Fig. 64, y, z). It is perforated posteriorly to 
admit the optic nerve. 

62. The choroid is the second or middle coat of the eyeball, 
and lies closely attached to the inner surface of the sclerotic. 
Unlike the latter, its structure is soft and tender ; it is dark 
in color, and possesses a great abundance of blood-vessels. Its 
dark color is due to a layer of dark brown or chocolate-colored 
cells spread out over its inner surface. This dark layer serves 
to absorb the rays of light after they have traversed the trans- 
parent structures in front of it. If the rays were reflected 
from side to side within the eye, instead of being thus absorbed, 
confused vision would result from the multitude of images 
which would be impressed upon the optic nerve. 

63. This mechanism has been unconsciously imitated by the 
opticians, who, when they make a microscope or telescope, take 
care that the interior of its tube shall be coated with a thick 
layer of black paint or lamp-black ; for without it, a clear 
delineation of the object to be viewed is impossible. The 
albinos, in whom these dark cells of the choroid are wanting, 
have imperfect vision, especially in the daytime and in strong 
lights. The dark cells are also wanting in white rabbits, 
and other animals that have red or pink eyes; their vision 
appears to be imperfect in the presence of a bright light. 

64. The Iris. — Continuous with the choroid, in the front 
part of the globe of the eye, is a thin, circular curtain, which 



62. The second or middle coat of the eyeball ? Its (lark color f 

63. Similar mechanism In microscopes ? The albinos 1 White rabbits ? 

64. What is the iris ? Its construction f llow is the si/.e of the pupil re^ulateil 



294 



THE SPECIAL SENSES 



occasions the brown, blue, or gray color of the eye in different 
individuals. On account of the varieties of its color, this 
membrane has received the 
name Iris, which is the 
Greek word for " rainbow " 
(see Fig. 64, i). A front 
view of it is shown in Fig. 
63. The iris is pierced in 
its centre by a round open- 
ing, called the pupil (p), 
which is constantly vary- 
ing in size. In olden times 
it was spoken of as the 
"apple of the eye." The 
hinder surface of the iris, 
except in albinos, has a 
layer of dark coloring mat- 
ter resembling that of the 
choroid. The iris is a muscular 
distinct sets of fibres, one of 




Fig. 65. — Front Section of the Eyeball, 
viewed from behind, and showing sus- 
PENSORY Ligament, Iris, and Pupil 



organ, and contains two 
which is circular, while the 
other radiates outward from the pupil. Their action regulates 
the size of the pupil ; for when the circular set acts, the open- 
ing contracts. Their action is involuntary, and depends on 
the reflex system of nerves, which causes the contraction of 
the pupil when a strong light falls upon the eye, and its expan- 
sion when the illumination is feeble. The suspensory ligament 
holds the crystalline lens in its place. (Fig. 65.) 

65. The iris, accordingly, serves a very useful purpose in 
regulating the admission of light to the eye (see Fig. 65). It, 
however, does not act instantaneously; and hence, when we 
pass quickly from a dark room into the bright sunlight, the 
vision is at first confused by the glare of light, but as soon as 
the pupil contracts, the ability to see becomes perfect. On the 
other hand, when we enter a dark apartment, such as a cellar, 
for a short time we can see nothing clearly ; but as soon as the 



65. The admission of light to the eye * The action of the iris under different circum- 
stances ? The lustre of the eye, how affected in youth and old age ? 



THE SPECIAL SENSES 295 

pupil expands and admits more light, we are enabled to distin- 
guish the surrounding objects. Animals of the cat species, 
and others which prowl around after nightfall, are enabled to 
see in the dark by having the iris very dilatable. The size of 
the pupil affects the lustre of the eye. When it is large, as it 
usually is during youth, the eye appears clear and brilliant ; 
while in old age the pupil is small and the eye is dull. The 
brilliancy of the eye is in part, at least, dependent upon the 
reflection of light from the front surface of the crystalline 
lens. 

66. Certain poisonous vegetables have the property of caus- 
ing the pupil to dilate, and have been used in small doses to 
increase the beauty of the eye. One of these drugs has been 
so largely used by the ladies for this purpose that it has 
received the name belladonna, from' the Italian words meaning 
" beautiful lady." This hazardous practice has resulted more 
than once in the death of the person desiring thus to increase 
her personal attraction. The common English name for bella- 
donna is " deadly nightshade." (In the diagram on page 290 
the shape and relations of the iris are more accurately shown 
than in the figures referred to above.) 

67. The Retina constitutes the third and inner coat of the 
globe of the eye. This, the important part of the eye that is 
sensitive to light, is a kind of nervous membrane, formed by 
the expansion of the optic nerve. Its texture is soft, smooth, 
and very thin ; it is translucent and of an opaline, or grayish- 
white color. It is sensitive to light alone ; and if any form of 
mechanical irritation be applied to it, the sensations of touch 
and pain are not experienced, but flashes of fire, sparks, and 
other luminous appearances are perceived. Thus an electric 
shock given to the eyeball occasions a flash of light; and a 
sudden fall, or a blow upon the eye, is often apparently accom- 
panied by the vision of " stars." 

68. These phenomena, are due to what is termed tin 4 " specific 

66. Means used to Increase the beauty of ttu> eye V The injurious consequences t 

67. What part does the retina constitute ? Hbwformed? its texture? Color} s<>nsi- 

tiveness ? 

68. Specific energy of the optic nerve ? Trial in Germany ? 



296 THE SPECIAL SENSES 

energy " of the optic nerve, which nerve, in common with the 
other nerves of the special sense, obeys a general law of nature, 
which requires that, whenever one of these nerves is stimulated, 
it shall respond with the sensation peculiar to itself. These 
flashes of retinal light have no power to illuminate external 
objects, although the opposite of this statement has been main- 
tained. On the occasion of a remarkable trial in Germany, it 
was claimed by a person who had been severely assaulted on a 
very dark night, that the flashes of light caused by repeated 
blows upon the head enabled him to see with sufficient distinct- 
ness to recognize his assailant. But the evidence of scientific 
men entirely refuted this claim, by pronouncing that the eye, 
under the circumstances named, was incapacitated for vision. 
Too intense light occasions a feeling of pain, but it is of a 
peculiar kind, and is termed " dazzling.'' 

69. All parts of the retina are not equally sensitive, and 
singularly enough, the point of entry of the nerve of sight in 
the back part of the eyeball is entirely insensible to light, and 
is called the " blind spot." The existence of this point may 
be proved by a simple experiment. Hold the accompanying 
figure, on page 283, directly in front and parallel with the eyes. 




Close the left eye, and fix the sight steadily on the left-hand 
circle ; then, by gradually varying the distance of the figure 
from the eye, at a certain distance (about six inches), the right- 
hand circle will disappear, but nearer or further than that, it 
will be plainly seen. The other eye may be also tried, with a 
similar result : if the gaze be directed to the right-hand circle, 
the left one will seem to disappear. The experiment may be 

69. Sensitiveness of all parts of the retina ? Experiment to prove the existence of the 
"blind spot" ? 



THE SPECIAL SENSES 297 

repeated by using two black buttons on the marble top of a 
bureau, or on some other white surface.. The blind spot does 
not practically interfere with vision, since the eye is seldom 
fixed immovably on an object, and the insensitive parts of the 
two eyes can never be directed upon the same object at the 
same time. 

70. Impressions made upon the retina are not at once lost, 
but continue a measurable length of time, and then gradually 
fade away. Thus, a bright light, or color, gazed at intently, 
cannot be immediately dismissed from sight by closing or turn- 
ing away the eyes. A stick lighted at one end, if whirled 
around rapidly in the dark, presents the appearance of an un- 
broken luminous ring ; and the spokes of a rapidly revolving 
carriage-wheel seem to be merged into a plane surface. If an 
object move too rapidly to produce this sort of lasting impres- 
sion, it is invisible, as in the case of ' a cannon-ball passing 
through the air in front of us. 

71. If a card, painted with two primary colors — as red and 
yellow — be made to rotate swiftly, the eye perceives neither 
of them distinctly ; but the card appears painted with their 
secondary color — orange. The average duration of retinal 
images is estimated at one-eighth of a second ; and it is because 
they thus endure, that the act of winking, which takes place 
so frequently, but so quickly, is not noticed and does not inter- 
rupt the vision. The retina is easily fatigued or deprived of 
its sensibility. After looking steadfastly at a bright light, or 
at a white object on a black ground, a dark spot corresponding 
in shape to the bright object, presents itself in whatever direc> 
tion we look. This spot passes away as the retina resumes its 
activity. 

72. If a bright color be gazed at intently, and the eyes then 
be turned to a white surface, a spot will appear ; but its color 
will be the complement of that of the object, Fix the eye 
upon a red wafer upon a white ground, and on removing the 



70. Duration of impressions upon the retina ? How Illustrated ? 

71. What further illustration ? Winking, why it is not noticed ? Base with whioh the 
retina is fatigued or deprived of sensibility '.' How shown ? 

7'2. How further shown ? How is the result accounted for J "Color-blindness"? 



298 THE SPECIAL SENSES 

wafer a greenish, spot of the same shape takes its place. This 
result happens because a certain portion of the retina has 
exhausted its power to perceive the red ray, and perceives only- 
its complementary ray, which is green. The color thus sub- 
stituted by the exhausted retina is called a physiological or 
accidental color. In some persons the retina is incapable of 
distinguishing different colors, when they are said to be affected 
with " color-blindness." Thus, red and green may appear alike, 
and then a cherry-tree, full of ripe fruit, will seem of the same 
color in every part. Eailroad accidents have occurred because 
the engineer of the train, who was color-blind, has mistaken the 
color of a signal. (Bead Note 9.) 

73. The Crystalline Lens. — Across the front of the eye, just 
behind the iris, is situated the crystalline lens, enclosed within 
its own capsule. It is supported in its place partly by a deli- 
cate circular ligament, and partly by the pressure of adjacent 
structures. It is colorless and perfectly transparent, and has 
a firm but elastic texture. In shape, it is doubly convex, and 
may be rudely compared to a small lemon-drop. The front 
face of the lens is flatter than the other, and is in contact with 
the iris near its pupillary margin, as is represented in the dia- 
gram of page 290. It is only one-fourth of an inch thick. 

9. Color-blindness. — " Daltonism, or color-blindness, receives its 
name from the eminent English chemist who described this infirmity 
as it existed in his own case. It arises from an unnatural condition 
of the organs of vision which prevents the discrimination of certain 
colors. Some persons will mistake red for green ; so that ripe cherries on 
a tree appear the same as the leaves; others recognize only black and 
white. Persons thus affected are sometimes incapable of discriminating 
musical tones. The healthy eye ordinarily fails to discriminate between 
certain colors, blue and green especially, when viewed by artificial 
light. But even this may in a measure be overcome by training, so 
that an expert dealer in silk obtains a knowledge of the shades of blue, 
green, and violet, which is proof against the confusing influence of gas- 
light and tinted curtains. The eyes of persons who have much to do with 
colors are more liable to become overstrained than those dealing chiefly 
with rays of white light." — Flint's Physiology (in part). 



73. The location of the crystalline lens ? How supported ? Its color and texture ? 
Shape ? Size ? 



THE SPECIAL SENSES 299 

74. When this little body becomes opaque, and no longer 
affords free passage to the rays of light, as often happens with 
the advance of age, an affection termed " cataract " is produced. 
Between the crystalline lens and the cornea is a small space 
which contains the aqueous humor (see Fig. 64, a). This humor 
consists of five or six drops of a clear, colorless liquid very 
much like water, as its name implies. That part of the globe 
of the eye lying behind the lens is occupied by the vitreous 
humor, so called from its fancied resemblance to melted glass 
(Fig. 64, v). This humor is a transparent, jelly-like mass, 
enclosed within an exceedingly thin membrane. It lies very 
closely applied to the retina, or nervous membrane of the eye, 
and constitutes fully two-thirds of the bulk of the eyeball. 

75. The Uses of the Crystalline Lens. — A convex lens has the 
property of converging the rays of light which pass through it; 
and the point at which it causes them to meet is termed its 




Fig. 67. —The Retinal Image 

focus. If a lens of this description, such as a magnifying or 
burning-glass, be held in front of an open window, in such a 
position as to allow its focus to fall upon a piece of paper, it 
will be found to depict upon the paper a miniature image of tin 1 
scene outside of the window. It will be further noticed that 
the image is inverted, or upside down, and that the paper at. 
the place upon which the image is thrown is much brighter 
than any other part. 

74. Cataract? Aqueous humor ? Vitreous humor ? 

76. What is a leus ami its ibeus ? The miniature linage, how produoed } 



300 THE SPECIAL SENSES 

. 76. Now all the transparent structures of the eye, but es- 
pecially the crystalline lens, operate upon the retina, as the 
convex lens acts upon the paper — that is, they paint upon the 
retina a bright, inverted miniature of the objects that appear in 
front of the eye (Fig. 67). That this actually takes place may 
be proved by experiment. If the eyeball of a white rabbit, the 
walls of which are transparent, be examined while a lighted 
candle is held before the cornea, an image of the candle-flame 
may be seen upon the retina. 

77. The form and structure of the crystalline lens endow it 
with a remarkable degree of refractive power, and enable it to 
converge all the rays of light that enter it through the pupil, 
to a focus exactly at the surface of the retina. When this lens 
is removed from the eye, as is frequently done for the cure of 
cataract, it is found that the rays of light then have their focus 
three-eighths of an inch behind the retina ; that the image is 
four times larger than in the healthy eye ; that it is less bril- 
liant, and that its outline is very indistinct. From this we 
learn that one of the uses of the crystalline lens is to make the 
retinal image bright and sharply defined, at the same time that 
it reduces its size. Indeed, the small size of the image is a 
great advantage, as it enables the limited surface of the retina 
to receive, at a glance, impressions from a considerable field of 
vision. 

78. As the image upon the retina is inverted, how does the 
mind perceive the object in its true, erect position? Many 
explanations have been advanced, but the simplest and most 
satisfactory appears to be found in the fact that the retina 
observes no difference, so to speak, between the right and left 
or the upper and lower positions of objects. In fact, the mind 
is never conscious of the formation of a retinal image, and 
until instructed, has no knowledge that it exists. Conse- 
quently, our knowledge of the relative location of external 
objects must be obtained from some other source than the ret- 



76. How are figures painted upon the retina ? How proved ? 

77. What can be said in respect to the form and structure of the crystalline lens ? 

78. How is the inverted image upon the retina presented in its true position to the mind ? 



THE SPECIAL SENSES 301 

ina. The probable source of this knowledge is the habitual 
comparison of those objects with the position of our own 
bodies; thus, to see an elevated object, we know we must raise 
the head and eyes ; and to see one at our right hand, we must 
turn the head and eyes to the right. 

79. Long-sight or Hyperopia, and Short-sight or Myopia. — 

The eye is not in all cases perfectly formed. For example, 
persons may from birth have the cornea too prominent or too 
flat, or the lens may be too thick or too thin. In either of 
these conditions sight will be more or less defective from the 
first, and the defect will not tend to disappear as life advances. 
The most common imperfection, however, is in the shape of 
the globe; which may be short (Fig. 68, h), as compared with 
the natural eye, n, or it may be too long, m. 

80. When the globe is short, only objects that are at a 
distance can be clearly seen, and the condition of the vision is 
known as " long-sight," or hyperopia. It will be observed, by 




Fig. 68. — The Different Shapes of the Globe of the Eve 

N, The Natural Eye M, The Short-sighted Eye 

H, The Long-sighted Eye S, Parallel Kays from the Sun 



reference to Fig. 68, that the focus of the rays of light would 
fall behind the retina of this eye. When the globe is too long, 
only objects that are very near to the eye can be clearly seen, 
and the condition resulting from this defect is termed " short- 
sight," or myopia. The focus of the rays of light is, in this 
case, formed in the interior of the eye in trout oi the retina. 



7S). The uniform perfection of the eye ? Examples ? The most common Imperfection} 
SO. How is "long-sight" explained ? "Short-sight " i 



302 THE SPECIAL SENSES 

81. Long-sight, or hyperopia, is common among school-chil- 
dren, nearly as much so as short-sight, and must not be 
confounded with the defect known as the "far-sight" of old 
people; although in both affections the sight is improved by 
the use of convex glasses. Children not infrequently discover 
that they see much better when they chance to put on the 
spectacles of old persons. For the relief of short-sight, con- 
cave glasses should be employed ; as they so scatter the rays 
of light as to bring the focus to the retina, and thus cause the 
vision of remote objects to become at once distinct. That form 
of " squint," in which the eyes are turned inward,^ is generally 
dependent upon long-sight, while that rarer form, when they 
turn outward, is due to short-sight. {Bead Note 10.) 

82. The Function of Accommodation. — If, after looking 
through an opera-glass at a very distant object, it is desired 
to view another nearer at hand, it will be found impossible 
to obtain a clear vision of the second object unless the adjust- 
ment of the instrument be altered, which is effected by means 
of the screw. If an object, like the end of a pencil, be held 
near the eye, in a line with another object at the other side of 

10. On the Production of Short-Sight. — ; 'The observations of Cohn 
in the schools and University of Breslau, of Kruger in Frankfort-on-the- 
Main, of Erismann in St. Petersburgh, of Von Hoffmann in Wiesbaden, 
and others abroad, prove most conclusively that one of the bad effects of 
school and college life is to produce diseases of the eyes. They have 
shown that near-sightedness increases rapidly in frequency as you go up 
in the scale of schools from the primaries of the rural districts to the 
universities. The gravity of this finding may be appreciated when we 
remember that near-sightedness is a disease, and that it very frequently 
descends from one generation to another, marked by such organic changes 
in the eyes as tend to the production of the worst forms of the malady, 
and to blindness. In 1867, Cohn, of Breslau, published the results of the 
examination of the eyes of 10,060 scholars. His examinations covered 
the entire range of school life. He found that 1,750 of the 10,060 children 
had defective vision — about seventeen per cent. He also examined, 
without selection, 410 of the 964 students of the Breslau University, and 
found that not one-third had normal eyes." — Dr. C. R. Agnew. 



81. Long-sight, how common ? With what must it not be confounded ? Kind of glasses 
for short-sight ? Why ? Squint ? 

82. What is stated in connection with the opera-glass ? Experiment with pencil and dis- 
tant object ? 



THE SPECIAL SENSES 303 

the room, or out of the window, and the eye be fixed first 
upon one and then upon the other, it will be found that when 
the pencil is clearly seen, the further object is indistinct; and 
when the latter is seen clearly, the pencil appears indistinct, 
and that it is impossible to see both clearly at the same time. 
Accordingly, the eye must have the capacity of adjusting itself 
to distances, which is in some manner comparable to the action 
of the screw of the opera-glass. 

83. This, which has been called the function of accommoda- 
tion, is one of the most admirable of all the powers of the 
eye, and is exercised by the crystalline lens. It consists 
essentially in a change in the curvature of the front surface 
of the lens, partly through its own elasticity, and partly 
through the action of the ciliary muscle. When the eye is 
at rest — that is, when accommodated for a distant object — 




Fig. G9. — Thk Function of Accommodation 

The right half of the diagram shows the eye at rest. The left half shows the lens 
accommodated for near vision 

the lens is flatter and its curvature diminished (see Fig. 69) ; 
but when strongly accommodated for near vision, the lens 
becomes thicker, its curvature increases, and the image on 
the retina is made more sharp and distinct, Since a strong 
light is not required in viewing near objects, the pupil ion- 
tracts, as is shown in the left-hand half of the diagram. 

88. Function of accommodation ? In what dots it consist? How is the function 
explained ? 



304 THE SPECIAL SENSES 

84. Old-sight, or Presbyopia. — But this marvellously beauti- 
ful mechanism becomes worn with use ; or, more strictly speak- 
ing, the lens, like other structures of the body, becomes harder 
with the approach of old age. The material composing the 
lens becomes less elastic, the power to increase its curvature is 
gradually lost, and as a consequence, the person is obliged to 
hold the book farther away when reading, and to seek a 
stronger light. In a word, the function of accommodation 
begins to fail, and is about the first evidence that marks the 
decline of life. By looking at the last preceding diagram, and 
remembering that the t increased curvature of the lens cannot 
take place, it will be at once understood why old-sight is bene- 
fited in near vision by the convex lens, such as the spectacles 
of old people contain. It acts as a substitute for the deficiency 
of the crystalline lens. (Bead Note 11.) 

85. Astigmatism. — It often happens that the curvature of 
the cornea or of the crystalline lens, or of both, is not uniform. 
This is more often true of the cornea than of the crystalline 
lens. When this happens, rays of light which pass through 
that portion of the cornea (or lens) having a greater curvature, 
will be refracted to a focus more quickly than the rest. Under 
such circumstances the focus will not be a point, as it should 
be for perfect vision, but a line. Such an eye is astigmatic. 
This difficulty is very common, and should be corrected by 
glasses fitted for each case. 

11. The Choice of Glasses. — "The perfectly healthy, normal ej r e 
begins to need a glass for ordinary work at between forty and forty-five 
years of age — of course, we here exclude all debilitated conditions of the 
body resulting from disease. Now, then, comes the question — shall we 
put on glasses, and of what strength ? To answer some prevalent fallacies 
handed down from one generation to another, we cannot do better than 
quote from the highest authority, Prof. Bonders, who says : ' The opinion 
is rather general that we should refrain as long as possible from the use 
of convex glasses. But, is it not folly to weary the eyes and the mind 
together, without necessarily condemning ourselves to guess, with much 
trouble, at the forms which we could see pretty well with glasses ? ' 

"Strangely enough, people have fallen also into the opposite fault. 



84. Change of sight with the approach of old age ? Explain the change. 
S5. Astigmatism ? Its cure ? 



THE SPECIAL SENSES 305 

86. The Sense of Hearing — Sound. — Hearing is the special 
sense by means of which we are made acquainted with sound. 
What is sound ? It is an impression made upon the organs of 
hearing, by the vibrations of elastic bodies. This impression 
is commonly propagated by means of the air, which is thrown 
into delicate undulations in all directions from the vibrating 
substance. When a stone is thrown into smooth water, a wave 
of circular form is set in motion from the point where the 
stone struck, which, as it advances, constantly increases in size 
and diminishes in force. 

87. Somewhat resembling this is the undulation, or sound- 
wave, which is imparted by a sonorous vibration to the 
surrounding atmosphere. Its shape, however, is spherical, 
rather than circular, since it radiates upward, downward, and 
obliquely, as well as horizontally, like the wave in water. 
The rate of motion of this spherical wave of air is about 1050 
feet per second, or one mile in five seconds. In water, sound 
travels four times as fast as in air, and still more rapidly 
through solid bodies ; along an iron rod its velocity is equal 
to two miles per second. 

88. The earth, likewise, is a good conductor of sound. It 
is said that the Indian of our western prairies can, by listening 
at the surface of the ground, hear the advance of a troop of 
cavalry while they are still out of sight, and can even discrim- 
inate between their tread and that of a herd of buffaloes. Solid 
substances also convey sounds with greater power than air. 

Some have thought, by the early use of spectacles, to be able to preserve 
their power of vision, and have recommended and employed k conservative 
glasses.' If I am not mistaken, self-interest had something to do with 
this recommendation. So long as the eye does not err, and remains free 
from fatigue in the work required of it, its own power is sufficient, and it 
is inexpedient to seek assistance in the use of convex glasses." — Dr. 
B. Joy Jeffries. 

8(5. Hearing? What is sound ? How propagated commonly ? 

87. Sound-wave in the atmosphere ? Its shape? Rate of motion ? Sound In air, water, 

and solid bodies ? 

88. The earth as a conductor of sound? \V h;it has the western Indian been taught? 
Solid substances as conductors? As regards sound, in what respect is air necessary? 
Sound in a vacuum ? 



306 THE SPECIAL SENSES 

If the ear be pressed against one end of a long beam, the 
scratching of a pin at the other extremity may be distinctly 
heard, which will not be at all audible when the ear is removed 
from the beam. Although air is not the best medium for con- 
veying sound, it is necessary for its production. Sound can- 
not be produced in a vacuum, as is shown by ringing a bell in 
the exhausted receiver of an air-pump, for it is then entirely 
inaudible. But let the air be re-admitted gradually, then the 
tones become more and more distinct, and when the receiver is 
again full of air, they will be as clear as usual. 

89. All sonorous bodies do not vibrate with the same degree 
of rapidity, and upon this fact depends the pitch of the sounds 
that they respectively produce. The more frequent the num- 
ber of vibrations within a given time, the higher will be the 
pitch ; and the fewer their number, the lower or graver will it 
be. Now, the rate of the successive vibrations of different 
notes has been measured, and it has thus been found that if 
they are less than sixteen in a second, no sound is audible ; 
while, if they exceed 60,000 per second, the sound is very 
faint, and is painful to the ear. The extreme limit of the 
capacity of the human ear may be considered as included 
between these points, but the sounds which we ordinarily hear 
are embraced between 100 and 3000 vibrations per second. 

90. The ear, which is the proper organ of hearing, is the 
most complicated of all the structures that are employed in 
the reception of external impressions. The parts of which it 
is composed are numerous, and some of them are extremely 
small and delicate. Nearly all these parts are located in an 
irregularly shaped cavity hollowed out in the temporal, or 
" temple" bone of each side of the head. That part of the 
bone in which the auditory cavity is placed has the densest 
structure of all bones of the body, and has, therefore, been 
called the " petrous," or rocky part of the temporal bone. In 
studying the ear, it is necessary to consider it as divided into 
three portions, which are called, from their relative positions, 

89. Pitch ? To what due ? Capacity of ear ? 

90. The ear. Its divisions. 



THE SPECIAL SENSES 



307 



the external ear, the middle ear, and the internal ear. (In the 
diagram, Fig. 70, a, the first is not shaded, the second is lightly 
shaded, and the last has a dark background.) 

91. The External Ear. — The external portion of the organ 
of hearing, designated in Fig. 70, a, includes, first, that outer 
part (a), which is commonly spoken of as " the ear," but which 




Fig. 70. — The Ear and its Different Parts 

A, Diagram of the Ear 
a, b, External Ear d, Middle Ear 

c, Membrana tympani e, Internal Ear 

B to B'", Bones of the Middle Ear (magnified) 
C, The Labyrinths or Internal Ear (highly magnified) 

in fact is only the portal of that organ; and, secondly, the 
auditory canal (b). The former consists of a flat, flexible piece 
of cartilage, projecting slightly from the side of the head, 
attached to it by ligaments, and supplied with a few weak 
muscles. Its surface is uneven, and curiously curved, and from 
its resemblance to a shell it has been called the concha. It 
probably serves to collect sounds, and to give them an inward 
direction, although its removal is said not to impair the acute- 
ness of hearing more than a few days. 



91. Of what does the external portion of the organ of hearing consist? Describe the 
portal of that organ known as the ear. Its use ? 



308 THE SPECIAL SENSES 

92. In those animals whose hearing is more delicate than 
that of man, the corresponding organ is of greater importance, 
it being larger, and supplied with muscles of greater power, 
so that it serves as a natural kind of ear-trumpet, which is 
easily movable in the direction of any sound that attracts the 
attention of the animal. Bold, preying animals generally have 
the concavity of this organ directed forward, while in timorous 
animals, like the rabbit, it is directed backward. Fishes have 
no outer ear, but sounds are transmitted directly through the 
solid bones of the head, to the internal organ of hearing. 

93. The auditory canal (Fig. 70, a, b), which is continuous 
with the outer opening of the ear, is a passage an inch and 
a quarter in length, its inner extremity being bounded by a 
closely fitting, circular membrane. This canal is of oval form, 
is directed forward and inward, and is slightly curved, so that 
the inner end is ordinarily concealed from view. The pouch 
of the skin which lines this passage is smooth and thin, 
especially at the lower end, where it covers the membrane 
just mentioned. 

94. As in the case of the nostrils, a number of small, stiff 
hairs garnish the margin of the auditory canal, and guard it, 
to some extent, against the entrance of insects and other for- 
eign objects. The skin, too, covering its outer half, is furnished 
with a belt of little glands which secrete a yellow, bitter sub- 
stance, called " ear-wax," which is especially obnoxious to small 
insects. As the outer layer of this wax-like material loses its 
useful properties it becomes dry, and falls out of the ear in the 
form of minute, thin scales, a fresh supply being furnished 
from the little glands beneath. In its form, the auditory canal 
resembles the tube of an ear-trumpet, and serves to convey the 
waves of sound to the middle portion of the ear. 

95. The Middle Ear, or Tympanum. — The middle ear is a 
small cavity, or chamber, of irregular shape, about one-fourth 
of an inch across from side to side, and half an inch long (see 

92. The ear in the animals of delicate hearing ? Eabbit ? Fishes ? 

93. What is the auditory canal ? Describe it. 

94. How is it guarded and protected ? " Ear-wax " ? 

95. What is the middle ear ? Why called tympanum ? 



THE SPECIAL SENSES 



309 



Fig. 70, a, d). From the peculiar arrangement of its various 
parts it has very properly been called the tympanum, or the 
"drum of the ear." The middle ear, like the external canal, 
contains air. 

96. The circular membrane, already mentioned as closing the 
auditory canal, is the partition which separates the middle 
from the external ear, and is called the membrana tympani (c), 
and may be considered as the outer head of the drum of the 
ear. It is sometimes itself spoken of as the " drum," but this 




Fig. 71. — Showing the Internal Mechanism of the Ear (greatly enlarged} 

is incorrect, since a drum is not a membrane, but is the hollow 
space across which the membrane is stretched. This mem- 
branous drum-head is very tense and elastic, and so thin as to 
be almost transparent; its margin is fastened into a circular 
groove in the adjacent bone. Each wave of sound that touches 
this delicate membrane causes it to vibrate, and it, in turn, 
excites movements in the parts beyond. 

97. Within the tympanum is arranged a chain of remark- 
able "little bones," or ossicles. They are chiefly three in 



90. What is the membrana tympani ? Describe it. 

97. What are thoossiolos? Their number and names! Their arrangement ? 



310 THE SPECIAL SENSES 

number, and from their peculiar shapes bear the following 
names : malleus, or the mallet ; incus, or the anvil ; and stapes, 
or the stirrup. A fourth, the smallest bone in the body, in 
early life intervenes between the incus and the stapes, but at 
a later period it becomes a part of the incus. It is called the 
orbicular bone. Small as are these ossicles — and they, together, 
weigh only a few grains — they have their little muscles, carti- 
lages, and blood-vessels, as perfectly arranged as the larger 
bones of the body. One end of the chain of ossicles, the mal- 
let, is attached to the membrane of the tympanum, or outer 
drum-head, while the other end, the stirrup, is firmly joined 
by its foot-piece to a membrane in the opposite side of the 
cavity. The chain, accordingly, hangs suspended across the 
drum between the two membranes ; and when the outer one 
vibrates under the influence of the sound-wave, the chain 
swings inward and transmits the vibration to the entrance of 
the inner ear. 

98. The musical instrument, the drum, is not complete if 
the air within be perfectly confined; we therefore find in all 
instruments of this kind a small opening in the side, through 
which air may pass freely. By this means the pressure of the 
air upon the vellum which forms the head of the drum is made 
equal upon all sides, and the resonance of the drum remains 
unaffected by the varying density of the atmosphere. It will, 
therefore, emit its proper sound, whether it be struck in the 
rarefied air of the mountain-top, or in the condensed air of a 
mine. The tympanum, or drum of the ear, in like manner has 
an opening, by means of which it communicates freely with 
the external air. This opening is a narrow canal, about an 
inch and a half long, called the Eustachian tube, after the name 
of its discoverer, Eustachius. 

99. The course of this passage is indicated in Tig. 71, 
directed downward and inward: its other extremity opens 
into the upper part of the throat. The passage itself is ordi- 
narily closed, but whenever the act of swallowing or gaping 

98. The Eustachian tube ? Describe it, and state its use. 

99. What can you state of the action of the Eustachian tube ? 



THE SPECIAL SENSES 



311 



takes place, the orifice in the throat is stretched open, and the 
air of the cavity of the tympanum may then be renewed. Air 
may at will be made to enter through this tube, by closing the 
mouth and nose, and then trying to force air through the latter. 




Fig. 72. —Section of the Right Ear 

E, Incus, or Anvil 
M, Malleus, or Mallet 



A, The Concha 

B, Auditory Canal 

C, Membrane of the Drum 

(the lower half) 

D, A Small Muscle 



I, Eustachian Tube 

G-, Semicircular Canals 

H, Cochlea, or Snail's Shell 



When this is done, a distinct crackle or clicking sound is per- 
ceived, due to the movement of the membranes, and of the 
little bones of the ear. 

100. The Eustachian tube serves, also, as an escape-pipe for 
the fluids which form within the middle ear ; and hence, when 
its lining membrane becomes thickened, in consequence of a 
cold or sore throat, and the passage is thus more or less choked 
up, the fluids are unable to escape as usual, and therefore 
accumulate within the ear. When this takes place, the vibra- 
tions of the membrane are interfered with: the sounds heard 



100. What other purpose does the Eustachian tube servo? How is this shown? 
" Throat-deafness " ? Primary use of the Eustachian tube ? 



312 THE SPECIAL SENSES 

appear muffled and indistinct; and a temporary difficulty of 
hearing, which is known as "throat-deafness," is the result. 
This result resembles the effect produced by interrupting the 
vibrations of a sonorous body, such as all are familiar with ; 
if the finger be placed upon a piano-string or bell when it is 
struck, the proper sound is no longer fully and clearly emitted. 
But the primary use of this tube is to afford a free communi- 
cation between the middle ear and the external atmosphere, 
and thus secure an equal pressure upon both sides of the mem- 
brane of the drum of the ear, however the density of the atmos- 
phere may vary. If, from undue tension of the membrane, 
pain is experienced in the ears, when ascending into a rare 
atmosphere, as in a balloon, or descending into a dense one, 
as in a diving-bell, it may be relieved by repeating the act of 
swallowing, from time to time, in order that the inner and 
outer pressure may thus be promptly equalized. 

101. The Internal Ear, or Labyrinth. — The most essential 
part of the organ of hearing is the distribution of the auditory 
nerve. This is found within the cavity of the internal ear, 
which, from its exceedingly winding shape, has been termed 
the labyrinth (see Fig. 70, c). This cavity is hollowed out in 
dense bone, and consists of three parts — the vestibule (a), or 
ante-chamber, which is connected with the other two ; the coch- 
lea (b), or snail's shell ; and the three semicircular canals (c). 
The manner in which the nerve of hearing is distributed is 
remarkable, and is peculiar to this nerve. In the vestibule 
and the canals its fibres are spread out over the inner surface, 
not of the bony cavity, but of a membranous bag, which con- 
forms to and partially fills that cavity, and which floats in it, 
being both filled and surrounded with a clear, limpid fluid. 

102. A singular addition to the mechanism of hearing is 
observed within this membranous bag of the labyrinth. This 
consists of two small oval ear-stones, and a quantity of fine 
powder of a calcareous nature, which is called " ear-sand." 
When examined under the microscope, these sandy particles 

101. The essential part of the organ of hearing ? Its location ? Formation ? 

102. Where is the " ear-sand " found ? Give the theory as to its use. 



THE SPECIAL SENSES 313 

are seen to lie scattered upon and among the delicate filaments 
of the auditory nerve ; and it is probable that, as the tremulous 
sound-wave traverses the fluid of the vestibule, the sand rises 
and falls upon the nerve-filaments, and thus intensifies the 
sonorous impression. 

103. In the cochlea, or snail's shell, which contains the 
fluid, but no membrane, the nerve branches upon a spiral 
shelf, which, like the cochlea itself, takes two and a half 
turns, growing continuously smaller as it winds upward. As 
many as three thousand nerve-fibres of different lengths have 
been counted therein; these, it has been thought, form the 
grand, yet minutely small key-board, upon which strike all the 
musical tones that are destined to be conveyed to the brain. 
The vestibule, it is also supposed, takes notice of noise as 
distinguished from musical sounds ; while the office of the 
semicircular canals is, in part at least, to prevent internal 
echoes, or reverberations. 

104. The vestibule communicates with the chain of bones of 
the middle ear by means of a small opening, called the " oval 
window," or fenestra ovalis. Across this window is stretched 
the membrane, which has already been alluded to as being 
joined to the stirrup-bone of the middle ear. Through this 
window, then, the sound-wave, which traverses the external 
and middle ear, arrives at last at the labyrinth. The limpid 
fluid which the latter contains, and which bathes the terminal 
fibres of the nerve of hearing, is thus agitated, the nerve-fibres 
are excited, and a sonorous impression is conducted to the 
brain, or, as we say, a sound is heard. 

105. Protection of the Sense of Hearing. — From what has 
been seen of the complicated parts which compose the organ of 
hearing, it is evident that while many of them possess an 
exquisite delicacy of structure, Nature has well and amply 
provided for their protection. We have observed the concealed 

108. In the cochlea, or snail's shell ? " Key-hoard " in the internal ear * The vestibule I 
Semicircular canals ? 

104. With what does the vestibule communicate ? What is the method by which sound 
is conducted to the brain ? 

105. The formation of the organ of hearing with a view to its protection J 



314 THE SPECIAL SENSES 

situation of the most important parts of the mechanism of the 
ear — the length of its cavity, its partitions, the hardness of 
its walls, and its communication with the atmosphere : all 
these provisions rendering unnecessary any supervision or care 
on our part in reference to the interior of the ear. But in 
respect to its external parts, which are under our control and 
within the reach of harm, it is otherwise. We may both 
observe the dangers which threaten them, and learn the means 
necessary to protect them. 

106. Caution. — One source of danger to the hearing consists 
in lowering the temperature of the ear, especially by the intro- 
duction of cold water into the auditory canal. Every one is 
familiar with the unpleasant sensation of distension, and the 
confusion of sounds which accompany the filling of the ear 
with water when bathing : the weight of the water within it 
really distends the membrane, and the cold chills the adjacent 
sensitive parts. It is not surprising, therefore, that the fre- 
quent introduction of cold water, and its continued presence in 
the ear, enfeebles the sense of hearing. Care should be taken 
to remove water from the ear after bathing, by holding the 
head on one side, and, at the same time, slightly expanding 
the outer orifice, so that the fluid may run out. For a like 
reason, the hair about the ears should not be allowed to remain 
wet, but should be thoroughly dried as soon as possible. 

107. It may be stated as a general rule, to which there are 
but few exceptions, that no cold liquid should ever be allowed 
to enter the ear. When a wash or injection is rendered neces- 
sary, it should always be warmed before use. The introduction 
of cold air is likewise hurtful, especially when it pours through 
a crevice directly into the ear, as it may often do through the 
broken or partially closed window of a car. The avoidance of 
this evil gives rise to another almost as great, namely, the 
introduction of cotton or other soft substances into the ear to 
prevent it from " catching cold." This kind of protection 
tends to make the part unnaturally susceptible to changes of 

106. Danger to which hearing may be subjected ? Advice. 

107. The general rule as to the use of water for the ear ? 



THE SPECIAL SENSES 315 

temperature, and its security seems to demand the continued 
presence of the "warm" covering. As a consequence of its 
presence, sounds are not naturally conveyed, and the sensitive- 
ness of the nerve of hearing is gradually impaired. 

108. The chief source of injury, however, to the ear is 
from the introduction of solid substances into the auditory 
canal, with the design of removing insects or other foreign 
objects that have found their way into the ear, or with the 
design of scraping out the ear-wax. For displacing a foreign 
object, it is usually sufficient to syringe the ear gently with 
warm water, the head being so held that the fluid easily 
escapes. If a live insect has gained entrance to the ear, it 
may first be suffocated by pouring a little oil upon it, and 
afterward removed by syringing the ear as just mentioned. 

109. The removal of ear-wax is generally unnecessary ; for, 
as we have before seen, Nature provides that the excess of it 
shall become dry, and then spontaneously fall out in the form 
of fine scales. The danger from the introduction of solid 
implements into the outer ear is chiefly found in the fact that 
the membrane which lies at the bottom of it is very fragile, 
and that any injury of it is liable to impair permanently the 
hearing of the injured ear. 

110. How Alcohol affects the Special Senses. — The narcotic 
or benumbing influence of alcohol is felt by all forms of ner- 
vous tissue, and among them the nerves of special sense. Vision 
is more susceptible of injury by this poison than any of the 
other senses, and it may be either slightly impaired or wholly 
lost. There is, in such cases, a progressive loss of power in 
the optic nerve that can only be remedied by a perpetual 
abandonment, on the part of the sufferer, of alcoholic drink ; 
and even this must not be delayed too long after dimness of 
sight has commenced. 

111. Alcohol and Color-Blindness. — Progressive loss of 
color-perception has been noticed by physicians in persons 

108. Chief source of injury to the ear? Directions for removing foreign objects from 
the ear ? Of a live insect ? 109. The removal of ear-wax J 

110. Do those who drink alcohol have pood vision ? 

111. What about their perception of color 1 



316 THE SPECIAL SENSES 

who use liquor habitually, though not to the extent of intoxi- 
cation. This form of gradually growing "color-blindness" 
becomes a matter of highest importance, since it may occur 
in a railroad engineer, or pilot, who drinks, or in the case of 
some official responsible for the lives and limbs of travelers by 
steam. No persons who indulge in alcoholic beverages can 
safely be allowed to occupy trusts of this nature. 

112. Effect of Alcohol on Other Senses. — Hearing and taste 
are dulled by alcohol. Touch is indirectly robbed of its 
efficiency in a certain proportion of cases, where a tremor of 
the muscles of the arm, or the " palsy of drunkards," occurs. 
Fine penmanship or drawing, and the use of keen-edged tools, 
depend upon a delicate employment of touch ; but with a hand 
that shakes like the palsied limb of an aged man, this becomes 
an impossibility. In this way has alcohol deprived many a 
man of the means of his livelihood. This is said to be espe- 
cially true of those who belong to the class of topers who 
drink little and often. {Bead Note 13, page 238.) 

113. False Apparitions due to Alcohol — Delirium Tremens. — 

In certain diseases the eyes appear to see objects that do not 
in reality exist within their view. High fever is one of these 
diseases ; delirium tremens, or " the horrors," experienced by 
some hard drinkers, is another. The latter condition is marked 
by a variety of terrifying and loathsome creatures ; if there 
be any form of reptile that is especially repulsive to the 
delirious person, this is the form that is most liable to haunt 
him. These false images may be dimly seen at first, but as 
the disease progresses they generally become perfectly distinct, 
and real, and torturing ; many a victim has thrown himself 
down from a window, regardless of its height, in his eager 
haste to escape from his unreal visions. Alarming sounds, also, 
are heard in some cases of this disorder. 

114. The Effect of Tobacco upon Vision. — Oculists are nearly 
unanimous in the opinion that impairment of sight and even 

112. Other senses ? 

113. Are unreal objects ever seen as real ? How is delirium tremens described ? 

114. Has tobacco any influence over vision ? 



THE SPECIAL SENSES 



317 



its utter loss may result from tobacco smoking, the optic nerve 
being gradually impaired, as in the case of those who lose their 
sight by alcohol, as described in the foregoing paragraph of 
this Chapter, Section 109. There is a relief for this approach- 
ing blindness if the patient will consent to wholly abstain from 
tobacco ; and yet, " there are those who would rather smoke 
than see," and persist in the injurious habit in spite of every 
proper medical caution. 

115. Certain narcotic substances have an injurious influence 
over the sense of hearing ; among these are tobacco and coffee 
used in excess. The opium habit is injurious to the sense of 
sight. 



Contents of the Orbit 



fLids 



THE EYE 



Muscles 



Lachrymal 
I apparatus 



TOPICAL OUTLINE 

Eyeball. 
Muscles. 
Blood-vessels. 
| Nerves. 
I Fatty tissue. 

I Lachrymal or tear apparatus. 
Consist of folds of the skin. 

Lined with a mucous membrane (the conjunc- 
tiva) , which is also reflected over the front of 
the ball. 
Closed by the circular orbicularis muscle. 
I Upper lid raised by a special muscle. 

(Superior — turns the eyeball up- 
wards. 
I Inferior — turns the eyeball down- 
i wards. 
1 External — turns the eyeball 

outwards. 
I Internal — turns the eyeball in- 
{ wards. 

(Superior — turns the eyeball 
outwards and downwards. 
Inferior — turns the eyeball out- 
wards and upwards. 
I Lachrymal (/land — in the upper and outer part 
j of the orbit. 
\ Several small duets. 

I Constant. 
Secretion. . ■' Moistens the eyeball. 

I Carried off by the nasal duct. 



( 4 Recti 



I 2 Oblique 



115. Have alcohol ami tobacco together any Influence 1 Other Injuries ! 



318 



THE SPECIAL SENSES 



THE EYE . 

{continued) 



Coats 



Lens 



Chambers 



Optics 



' Outer 



f Sclerotic 

I 

I Cornea . 



Choroid 



Middle 



Interior 



Iris. 



Retina 



| Tough, fibrous, 

' opaque. 
f Transparent. 
Covers the front cen- 
tral portion of the 
I eye. 

r Contains black pig- 
ment. 
Terminates in front 
I by the ciliary 
I processes. 
f A circular perforated 
diaphragm. 
Aperture called the 

pupil. 
Pupil contracted by 
circular muscular 
fibres ; and 
Dilated by radial 
fibres, 
j Nervous structures. 
' Connective tissue. 



Aqueous 



Vitreous 



f Situated just behind the iris. 
Double convex. Elastic. 
Back surface more convex than the front. 
Enclosed in a capsule. 

Held by the suspensoi^y ligament at its circum- 
ference. 
Ligament relaxed by the contraction of the 
ciliary muscle. 

| Between the iris and the cornea. 

' Contains a watery fluid. 

I Includes the greater portion of 

j the ball. 

I Contains a transparent jelly-like 

[ substance. 
The eye a camera obscura or dark chamber. 
Kays of light converge as they enter the cornea. 
Convergence increased by the lens. 
Image (inverted) falls on the retina. 

( Cornea or lens too convex. 

1 Remedy — wear concave glasses. 

j Cornea or lens too flat. 

I Remedy — wear convex glasses. 

j At entrance of optic nerve. 

( Totally insensitive to light. 

f tit of an inch outside the blind 
spot. 

I Marked by a slight depression. 

[ Most sensitive part of the retina. 
Retina retains impressions for about g of a sec- 
ond after its exciting cause ceases. 



Short-sight , 
Long-sight , 
Blind spot . 

Yellow spot 



THE SPECIAL SENSES 



319 



Outer 



Middle 



Internal 



f Pinna .... 

Canal .... 

An irregular 
Bones .... 

Openings . . 



Osseous 
labyrinth 



f Cartilaginous framework. 

I Fatty tissue. 
J Muscles. 
1 Skin. 

I Collects sound waves and reflects 

[ them into the auditory canal. 

r 1\ iribh long. 

I Closed internally by the drum. 
1 Glands — secrete "wax." 

[ Hairs — directed outwards, 
cavity in the temporal bone. 

f Malleus. 
\ Incus. 

{ Stapes. 

( Fenestra 
stapes. 
Fenestra 



Membranous 
I labyrinth 



ovalis — closed by the 



rotunda — closed by a 
membrane, 
f Vestibule i Central portion. 
< fenestra ovalis. 
[ Three in number. 
\ Open into the vesti- 
[ bule. 

{A spiral tube. 
2| turns round the 
modiolus. 
Fenestra rotunda. 
Within the osseous. 
Similar in shape. 
Surrounded by perilymph. 
Contains endolymph. 
Otoliths and hair-like processes. 
Terminal fibres of auditory nerve. 



Canals 



I Cochlea 



QUESTIONS FOR TOPICAL REVIEW 

PAOE 

1. What is said of the production of sensation ? 204, 265 

2. What is said of the variety of sensation? 205 

3. What is said of the general sensibility ? 200 

4. What is said of the sensation of pain ? 261 

5. What is said of the uses of pain? 267-269 

6. Say what you can of the special sensation 269-271 

7. Say what you can of the organs of touch "J71 . 272 

8. Say what you can of the sense of touch 272-273 

9. Say what you can of the delicacy of touch 274. 275 

10. What is understood of the sensations of temperature and weight ?. 275, 276 

11. What is understood by the organ of taste ? 216. 211 

12. What is understood by the sense of taste ? 277. 27S 

13. What is understood by the relations of taste 279, 280 

14. Explain the influence of education, etc 280 

15. Explain the sense of smell 280. 28 1 



320 THE SPECIAL SENSES 

PAGE 

16. Explain the nerve of smell 281, 282 

17. Explain the uses of the sense of smell 282-284 

18. Explain the sense of sight 285, 286 

19. Give the statement concerning light and the optic nerve 286, 287 

20. Give the statement concerning the organ of sight 287, 288 

21. Give the statement concerning the orbits 288 

22. Give the statement concerning the eyelids 288, 289 

23. Give the statement concerning the lachrymal fluid 290, 291 

24. Give the statement concerning the eyeball 291-293 

25. Give the statement concerning the iris 293-295 

26. Give the statement concerning the retina 295-298 

27. Give the statement concerning the crystalline lens 298, 299 

28. What are the uses of the lens ? 299-301 

29. What about long and short sight ? 301, 302 

30. Explain the function of accommodation 302, 303 

31. Explain old sight or presbyopia 304 

32. Explain hearing and sound 305-307 

33. Explain the external ear 307, 308 

34. Explain the middle ear 308-309 

35. Explain the internal ear 312, 313 

36. What is said of the protection of the sense of hearing ? 313, 314 

37. What caution is given? 314, 315 

38. How does alcohol affect the special senses ? 315, 316 

39. How does alcohol affect hearing, taste, and touch ? 316 

40. Effect of tobacco upon vision? 316, 317 



CHAPTER XI 

THE VOICE 

Voice and Speech — The Larynx, or the Organ of the Voice — The Vocal 
Cords — The Laryngoscope — The Production of the Voice — The Use 
of the Tongue — The Different Varieties of Voice — The Change of 
Voice — Its Compass — Purity of Tone — Ventriloquy 

1. Voice and Speech. — In common with the majority of the 
nobler animals, man possesses the power of nttering sounds, 
which are employed as a means of communication and expres- 
sion. In man these sounds constitute the voice ; in the animals 
they are designated as the cry. The song of the bird is a 
modification of its cry, which is rendered possible from the fact 
that its respiratory function is remarkably active. The sounds 
of the animals are generally produced by means of their 
breathing organs. Among the insects, they are sometimes 
produced by the extremely rapid vibrations of the wings in 
the act of flight, as in the case of the mosquito ; or by the 
rubbing together of hard portions of the external covering of 
the body, as in the cricket. Almost all kinds of marine ani- 
mals are voiceless. The tambour-fish and a few others have, 
however, the power of making a sort of noise in the water. 
(Bead Note 1.) 

2. But man alone possesses the faculty of speech, or the 
power to use articulate sounds in the expression of ideas, and 



1. Voice in Man and Animals. — " The human voice, taking male 
and female together, has a range of nearly tour octaves. Man's power 
of speech, or the utterance of articulate sounds, is due to his intel- 
lectual development more than to any great structural difference between 

him and the Apes. Song is produced by the glottis, speech by the 
mouth. The parrot and mocking-bird use the tongue in imitating 
human sounds." — Orion's Zoology. 



1. Tho uttering of sounds by animals? How produced ? 

2. Tlic evidenoe of man's superior endowment? What is stated of the idiot ? Parrot ? 
Raven ? 

C2I 



322 THE VOICE 

in the communication of mind with mind. Speech is thus an 
evidence of the superior endowment of man, and involves the 
culture of the intellect. An idiot, while he may have complete 
vocal organs and full power of uttering sounds or cries, is 
entirely incapable of speech ; and, as a rule, the excellence of 
the language of any people will be found to be proportional to 
their development of brain. Man, however, is not the only 
being that has the power to form articulate sounds, for the 
parrot and the raven may also be taught to speak by rote ; but 
man alone attaches meaning to the words and phrases he 
employs. 

3. Relation to Hearing. — Speech is intimately related to the 
sense of hearing. A child born deaf is, of necessity, dumb 
also ; not because the organs of speech are imperfect, for he 
can utter cries and may be taught to speak, and even to con- 
verse in a rude and harsh kind of language ; but because he 
can form no accurate notion of sound. A person, whose hear- 
ing is not delicate, or as it is commonly expressed, who "has 
no ear for music," cannot sing correctly. A person who has 
impaired hearing commonly talks in an unnaturally loud and 
monotonous voice. These examples show the necessary rela- 
tion of intelligence and the sense of hearing with that form of 
articulate voice which is termed speech. {Bead Note 2.) 

2. Certain Peculiarities of the Voice. — " Voice is a sound produced 
in the throat by the passage of the air through the glottis, as it is expelled 
from the lungs. It is grave and strong in man, soft and higher in women ; 
it varies according to age. It is alike in both sexes in infancy, but is 
modified in youth ; then the voice is said to 'change.' In the young 
woman it descends a note or two and becomes stronger. In the young 
man the change is much more strongly marked. At the fourteenth or 
fifteenth year the voice loses its regularity, becomes harsh and unequal ; 
the high notes cannot be sounded, while the grave ones make their 
appearance. A year is generally sufficient for this change to be complete, 
and the voice of the child gives place to that of the man. Exercise of the 
voice in singing should be very moderate, if not entirely suspended, while 
this change is going on. Voice is divided into singing and speaking 
voice. One differs from the other almost as much as noises do from 
musical sounds. It is the short duration of speaking sounds which dis- 



3. Speech and hearing ? A deaf child? Person having "no ear for music " ? Impaired 
hearing ? What do the examples show ? 



THE VOICE 323 

4. The Organ of the Voice. — The essential organ of the voice 
is the Larynx. This has been previously alluded to in its 
relation to the function of respiration^ and, in the chapter on 
that subject, are figured the front view of that organ (Fig. 48), 
and its connection with the trachea, tongue, and other neigh- 
boring parts (Fig. 51). It is situated at the upper part of the 
neck, at the top of the trachea, or tube by which air passes 
into and out of the lungs. The framework of the larynx is 
composed of four cartilages, which render it at once very 
strong and sufficiently flexible to enable it to move according 
to the requirements of the voice. 

5. The names of the cartilages are (1) the thyroid, which is 
a broad, thin plate, bent in the middle and placed in the 
central line of the front part of the neck, where it is known 
as the pomum Adami, or Adam's apple (Fig. 73, b), and where 
it may be felt moving up and down with each act of swallow- 
ing ; (2) the cricoid, which is shaped like a seal ring, with the 

tinguishes them from those of singing. This is proved by the fact that if 
we prolong the intonation of a syllable, or utter it like a note, the musical 
sound becomes evident. And if we pronounce all the syllables of a phrase 
in the same tone, the speaking voice closely resembles psalm-singing. 
Every one must have noticed this in hearing school-boys recite or read in 
a monotone, and the analogy is complete when the last two or three 
syllables are pronounced in a different tone. Spoken voice is moreover 
always a chant more or less marked, according to the individual and the 
sentiment expressed. The accentuation peculiar to certain languages also 
gives the speech the character of a chant ; to a French ear an Italian 
preacher seems always to sing. A chant also is caused by those inflec- 
tions of the voice, which express our emotions and our passions. They 
extend from the feeble murmur, which the ear scarcely perceives, to the 
piercing cry of pain. Affectionate, sympathetic, imperious, or hostile, 
they sometimes charm, sometimes irritate, and always move us. It 
is related of Gretry, that he amused himself by noting as exactly as 
possible the ' Bonjour, monsieur !' of the persons who visited him ; and 
these words expressed by their intonation, in fact, the most opposite 
sentiments, although literally the same. Baron, the comedian, moved 
his audience to tears by his recitation of the stanzas of the song. • >7 h' 
roi m'avait donne Paris sa granftmlU ' — 'If the king had given me Paris 
his great city. 1 " — Lc Pileur on Wonders of the Human Body. 



4. Orpan of the voico ? Where situated ? Of what is Us framework composed f 
.\ Names, formation, and situation of the cartilages ? 



324 



THE VOICE 



broad part placed posteriorly (Fig. 73, e). At the top of the 
cricoid cartilage are situated the two small arytenoid cartilages, 
the right one of which is shown in Fig. 73, c. These latter 
little organs are much more movable than the other two, and 
are very important in the production of the voice. They have 
a true ball-and-socket joint, and several small muscles which 
contract and relax with as perfect regularity and accuracy as 
any of the larger muscles of the body. 

6. The interior of the larynx is lined with a very sensitive 
mucous membrane, which is much more 
closely adherent to the parts beneath 
than is usually the case with membranes 
of this description. The epiglottis (a), 
consisting of a single leaf-shaped piece 
of cartilage, is attached to the front part 
of the larynx. It is elastic, easily moved, 
and fits accurately over the entrance to 
the air-passages below it. Its office is 
to guard these delicate passages and the 
lungs against the intrusion of food and 
other foreign articles, when the act of 
swallowing takes place. It also assists 
in modifying the voice. 

7. The Vocal Cords. — Within the 
larynx, and stretched across it from the 
thyroid cartilage in front to the ary- 
tenoid cartilages behind, are placed the 
two sets of folds called the vocal cords. 
The upper of these, one on each side, 




Fig. 73. — Section of the 



Laryxx and Trachea 



are the false cords, which are compara- A > The Epiglottis 

, n , , . n .,, rm. B. The Thyroid Cartilage 

tively fixed and inflexible. Inese are c, Arytenoid cartilage 
not at all essential to the formation of £• I entr J ] r e of } he ^ nx 

h., Cricoid C artilage 

vocal sounds, for they have been injured, r. Eight Vocal cord 

in those lower animals whose larynx 

resembles that of man, without materially affecting their 

characteristic cries. Below these, one on each side, are the 

6. Lining of the interior of the larynx ? The epiglottis ? 

7, Where are the vocal cords ? The false cords ? The true cords? 



THE VOICE 



325 



two vocal cords (Fig. 73, f), which pursue a similar direction 
to the false cords — namely, from before backward. They are 
composed of a highly elastic, though strong tissue, and are 
covered with a thin, tightly fitting layer of mucous membrane. 
Their edges are smooth and sharply defined, and when they 
meet, as they do in the formation of sounds, they exactly 
match each other. 

8. Between the true and false vocal cords is a depression on 
each side, which is termed the ventricle of the larynx (Fig. 
73, d). The integrity of these two cords, and their free vibra- 
tion, are essential to the formation of the tones and the modu- 
lation of the natural voice. This is shown by the fact that, if 
one or both of these cords are injured or become diseased, 
voice and speech are weakened ; or when the mucous mem- 
brane covering them becomes thickened, in consequence of a 
cold, the vocal sounds are rendered husky and indistinct. 
"When an opening is made in the throat below the cords — as 
not infrequently occurs in consequence of an attempt to com- 
mit suicide — voice is impossible except when the opening is 
closed by external pressure. 

9. The interval or space between the true cords of the voice is 
constantly varying, not only when their vocal function is in ex- 
ercise, but also during the act 
of respiration. Every time 
the lungs are inflated, the 
space increases to make wide 
the entrance for the air. and 
diminishes slightly during ex- 
piration. So that these little 
cords move gently to and fro 
in rhythm with the expansion 
and contractioD o{ the chest 
in breathing. These move- 
ments and others may be 
seei] to take place, it a small 




Pio. 74. —A View of the Vocal Cords 
Means of the Laryngoscope 



Tl 



8. Where is (he ventricle of the lur; 

and modulation of the voice ? 

0. Variation in the interval between the true cords ol' the voii 



to the formation of the tone: 



Experiment with tho 



326 THE VOICE 

mirror attached to a long handle be placed back into the 
upper part of the throat; the handle near the mirror must 
be bent at an angle of 45°, so that we may look "around 
the corner," so to speak, behind the tongue. The position 
which the mirror must assume will be understood by refer- 
ence in Fig. 51. A view of what may be seen under favor- 
able circumstances, during tranquil inspiration, is represented 
in Fig. 74. The vocal cords are there shown as narrow, 
white bands ; on each side of the central opening, and since 
the image is inverted, the epiglottis appears uppermost. The 
rings partly seen through the opening belong to the trachea, 
This little mirror is the essential part of an instrument, which 
is called the laryngoscope, and simple as it may seem, it is 
accounted one of the most valuable of the recently-invented 
appliances of the medical art. 

10. The Production of the Voice. — During ordinary tranquil 
breathing, no sound is produced in the larynx, true vocal tones 
being formed only during forcible expiration, when, by an 






Fig. 75. — The Different Positions of the Vocal Cords 

A, The position during inspiration. B, In the formation of low notes. C, In the formation 

of high notes 

effort of the will, the cords are brought close together, and are 
stretched so as to be very tense. The space between them is 
then reduced to a narrow slit, at times not more than y-J-g- of 
an inch in width ; and the column of expired air being forced 
through it causes the cords to vibrate rapidly, like the strings 
of a musical instrument. Thus the voice is produced in its 
many varieties of tone and pitch; its intensity, or loudness, 
depending chiefly upon the power exerted in expelling the air 

10. The formation of true vocal tones ? 



THE VOICE 327 

from the lungs. When the note is high, the space is dimin- 
ished both in length and width ; but when it is low, the space 
is wider and longer (Fig. 75, b, c), and the number of vibra- 
tions is fewer within the same period of time. 

11. The personal quality of the voice, or that which enables 
us to recognize a person by his speech, is mainly due to the 
peculiar shape of the throat, nose, and mouth, and the reso- 
nance of the air contained within those cavities. The walls of 
the chest and the trachea take part in the resonance of the 
voice, the air within them vibrating at the same time with 
the parts above them. This may be tested by touching the 
throat or breast-bone, when a strong vocal effort is made. The 
teeth and the lips also are important, as is shown by the 
unnatural tones emitted by a person who has lost the former, 
or by one who is affected with the deformity known as " hare- 
lip." The tongue is useful, but not indispensable to speech; 
the case of a woman is reported, from whom nearly the whole 
tongue had been torn out, but who could, nevertheless, speak 
distinctly and even sing. 

12. The Varieties of voice are said to be four in number; 
two, the bass and tenor, belonging to the male sex ; and two, 
the contralto or alto, and soprano, peculiar to the female. The 
baritone voice is the name given to a variety intervening 
between the bass and tenor. In man, the voice is strong and 
heavy ; in woman, soft and high. In infancy and early youth, 
the voice is the same in both sexes, being of the soprano 
variety : that of boys is both clear and loud, and being sus- 
ceptible of considerable training, is highly prized in the elioral 
services of the church and cathedral. At about fourteen years 
of age the voice is said to change — that is, it becomes hoarse 
and unsteady by reason of the rapid growth of the larynx. In 
the case of the girl, the change is not very marked, except 
that the voice becomes stronger and has a. wider compass ; but 
in the boy, the larynx nearly doubles its size in a single year, 
the vocal cords grow thicker, longer, and coarser, and t ho voice 



11. To what is the personal quality of the voice mainlj due ? What aids are there I 

12. Varieties of voice ? The baritone ? The voioe in early youth ? 



328 THE VOICE 

becomes masculine in character. During the progress of this 
change, the use of the voice in singing is injudicious. 

13. The ordinary range of each of the four varieties of the 
voice is about two octaves ; but this is exceeded in the case of 
several celebrated singers. Madame Parepa Rosa had a com- 
pass of three full octaves. When the vocal organs have been 
subjected to careful training, and are brought under complete 
control of the will, the tension of the cords becomes exact, 
and their vibrations become exceedingly precise and true. 
Under these circumstances the voice is said to possess " purity " 
of tone, and can be heard at a great distance, and above a 
multitude of other sounds. Some years ago the power of a 
pure voice to make itself heard was exemplified in a strik- 
ing manner at a musical festival held in an audience-room of 
extraordinary size ; and amid an orchestra of a thousand instru- 
ments and a chorus of twelve thousand voices, the artist named 
above also sang ; yet such was the purity and strength of her 
voice that its notes could be clearly heard rising above the 
vast waves of sound produced by the full accompaniment of 
chorus and orchestra. {Bead Note 3.) 

3. The Benefits of Vocal Exercise. — " Heading aloud and recitation 
are more useful and invigorating musical exercises than is generally imag- 
ined, at least when managed with due regard to the natural powers of the 
individual, so as to avoid effort and fatigue. Both require the varied 
activity of most of the muscles of the trunk to a degree of which few are 
conscious, till their attention is turned to it. In forming and undulating 
the voice, not only the chest, but also the diaphragm and abdominal 
muscles are in constant action, and communicate to the stomach and 
bowels a healthy and agreeable stimulus ; and consequently, where the 
voice is raised and elocution rapid, as in many kinds of public speaking, 
the muscular effort comes to be even more fatiguing than the mental. 
When care is taken, however, not to carry reading aloud so far at one 
time as to excite the least sensation of soreness or fatigue in the chest, 
and it is duly repeated, it is extremely useful in developing and giving 
tone to the organs of respiration, and to the general system. To the 
invigorating effects of this kind of exercise, the celebrated Cuvier was in 
the habit of ascribing his own exemption from consumption, to which, at 
the time of his appointment to a professorship, it was believed he would 
otherwise have fallen a sacrifice. The exercise of lecturing gradually 



13. The range of the voice ? Result of careful training- of the vocal organs ? 



THE VOICE 329 

14. In the production of the articulate sounds of speech, 
the larynx is not directly concerned, but those sounds really 
depend upon alterations in the shape of the air-passages above 
that organ. That speech is not necessarily due to the action of 
the larynx is proved by the following simple experiment. Let 
an elastic tube be passed through the nostril to the back of the 
mouth. Then, while the breath is held, cause the tongue, teeth, 
and lips to go through the form of pronouncing words, and, at 
the same time, let a second person blow through the tube into 
the mouth. Speech, pure and simple, or, in other words, a 
whisper is produced. Still further continue the experiment, 
while permitting vocal sounds to be made, and there will be 
produced a loud and whispering speech at the same moment ; 
thus showing that voice and speech are the result of two dis- 
tinct acts. Sighing, in like manner, is produced in the mouth 
and throat ; if, however, a vocal sound be added, the sigh is 
changed into a groan. 

15. Ventriloquism is a peculiar modification of natural 
speech, which consists in so managing the voice that words 
and sounds appear to issue, not from the person, but from 
some distant place, as from the chimney, the cellar, or the 
interior of a chest. The original meaning of the word ventril- 
oquism (that is, speaking from the belly) indicates the early 
belief that this mode of speech was dependent upon the 
possession and use of some special organ besides the larynx 
and mouth ; but at the present time it is known that it is 
produced by these organs alone, and that the sources of decep- 
tion consist, on the part of the performer, in the dexterous 
management of the voice, together with a talent for mimicry ; 
and, on the part of the auditory, in the liability of the sense 
of hearing to error in respect to the direction of sounds. The 

strengthened his lungs and improved his health so much that he was never 
afterward threatened with any serious pulmonary disease. Hut, of course, 
this happy result followed because the exertion of lecturing was not too 
great for the then existing condition of his lungs." ( \>mJn' y a Physiology, 



14. The production of the articulate sounds? What experiment Is mentioned '.■ 

15. What is ventriloquism ? indication of the original meaning of the word I llou an 
the ventriloquous sounds produced ? 



330 THE VOICE 

ventriloquist not only seems to " throw his voice," as it is said, 
or simulates the sound as it usually appears at a distance with 
but little motion of the lips and face, but he imitates the voices 
of an infant and of a feeble old man, of a drunken man dis- 
puting with an exasperated wife, the broken language of a 
foreigner, the cry of an animal in distress, demonstrating that 
the performer must be proficient in the art of mimicry. Ven- 
triloquism was known to the ancient Romans and Greeks ; and 
it is thought that the mysterious responses that were said to 
issue from the sacred trees and shrines of the oracles at 
Dodona and Delphi were really uttered by priests who had 
the power of producing this form of speech. {Bead Notes 4 and 5.) 

4. Improvement of Conversation by Vocal Training. — "For years 
I had fallen into a low, drawling, lazy tone of voice in my ordinary con- 
versation ; my utterance came forth in a cloud, and had its dwelling there. 
From divers experiments and observations I had long ago assured myself 
that this was a capital defect ; but this assurance had brought with it no 
reform. Now, at last, I attempted it in good earnest. I studied to bring 
myself out of my listlessness, to acquire a rapid, distinct, and articulate 
enunciation. No man can miss this acquisition unless from some organic 
infirmity, provided only that he pursue it steadily and earnestly. I em- 
ployed a variety of exercises for the voice, as recitation, the frequent 
repetition of the same passage, slowly at first, and then more quickly, up 
to my highest pitch of rapidity, the pronunciation of foreign languages, — 
Greek for the sake of fullness, and French for distinctness and despatch. 
As a result, I became comparatively a clear and satisfactory speaker ; and 
as my talk was more distinct my thoughts were all the more pointed and 
precise. I acquired an evenness of tone, a confidence, a complacency ; 
my conversation, as* the French say of their language, went of itself ; I 
had leisure to look chiefly to my direction, to march on to my object." — 
Self- Formation, by Capel Lofft. 

5. Ventriloquism and Sound-Painting. — "Ventriloquism bears the 
same relation to other phenomena of sound that perspective does to 
optical phenomena. The art of perspective consists in portraying upon a 
flat surface the appearance of objects at a distance from it, so that the 
same effect shall be produced upon the eye by the picture as would be 
produced by the objects themselves. In order to do this, the form, tints, 
and shades are reproduced, not as they really are, but as they are modified 
by position and distance. Or it may be said to consist in making and 
arranging a group of objects so that when viewed at a given distance they 
shall produce the same optical effect produced by another set of objects 
arranged in different positions and at different distances. 

" Ventriloquism consists in making and arranging sounds so that when 
heard at a given distance they shall produce the same effect upon the ear 



THE VOICE 



331 



that another set of sounds produce arranged in "different positions and at 
different distances. 

" Sounds from a distance are of course weakened, and they also have 
another quality which may be compared to the indistinctness of outline 
in objects seen at a distance. In proportion as the fine ear of the ven- 
triloquist can appreciate these modifications will be his success in imitating 
distant sounds. For as to see correctly is the first essential to success in 
drawing, so is hearing correctly the first essential in ventriloquism. 

" There are many sounds which cannot be imitated by voice merely, 
such as the singing of birds, the strident noise of a saw, the whistling of 
a plane, etc. Such and similar unmusical sounds are imitated by means 
of the teeth, the lips, or the soft parts of the mouth. Thus, the noise of 
a saw is like that produced by hawking, only much prolonged, and modi- 
fled by the cheeks ; singing of birds may be imitated by whistling through 
the teeth ; the foaming of soda-water by breathing with open lips into a 
tumbler, etc. To persons having a fine ear this amusing art is not difficult, 
but we object to the name applied to it. It ought to be called sound- 
painting." 



LARYNX 



Thyroid . 
Cricoid . . 

Arytenoid 

Glottis . . . 
Epiglottis . 

Vocal cords 



TOPICAL OUTLINE 

j The upper cartilage, 
i Wide in front ; open behind. 
( A complete ring of cartilage. 
I Wide behind ; narrow in front. 
[ Small pyramidal. 

Surmount the upper posterior edge of the 
cricoid. 
I Jointed with the cricoid. 

[.The communication between the pharynx and 
j the larynx. 

I Bounded on each side by the vocal cords. 
| A thin movable layer of cartilage. 
j Closes the glottis during the act of swal- 
l lowing. 

Bands of elastic fibres. 

Embedded in mucous membrane. 

Relaxed during quiet breathing. 

Stretched during speaking and singing. 

Attached to arytenoid cartilages behind, and 
to the thyroid in front. 



• • -I 



QUESTIONS FOR TOPICAL REVIEW 

PAOV 

1. What distinction is made between speech and voice? 321 

2. What is said of each ? 321, 322 

3. What does speech usually indicate '.' 822 

4. How is speech related to hearing ? 322 



332 THE VOICE 



PAGE 

5. Name and describe the organ of the voice 323 

6. What other organs are concerned ? 323 

7. What offices have the cartilages ? 323, 324 

8. Explain and locate the epiglottis 324 

9. Say what you can of the vocal cords 321-325 

10. State how a cold affects the voice 325 

11. What does the laryngoscope reveal to us ? 326 

12. Upon what does quality of voice depend ? 327 

13. What change takes place when the voice is raised ? 327, 328 

14. How do the chest and trachea take part ? 327 

15. How the teeth, lips and tongue ? 327 

16. What are the varieties of voice ? 327 

17. What changes take place with age ? 327, 328 

18. Mention the ordinary range of voice and instance an exception 328 

19. What further is said of speech ? 329 

20. What is ventriloquism? 329 

21. How produced ? 329 

22. What mysteries does it help to explain ? 330 



CHAPTER XII 

THE USE OF THE MICROSCOPE IN THE STUDY 
OF PHYSIOLOGY 

The Law of Tissues — Necessity of the Microscope — Different Kinds of 
Microscopes — Additional Apparatus — Preliminary Studies — The 
Study of Human Tissues — Tissues of the Inferior Animals — Incen- 
tives to Study 

1. The Law of the Tissues. — The will of an infinite Creator 
is obeyed by atoms as well as by worlds. He has seen fit to 
commit all the functions of life to structures or tissues so small 
as to be invisible to the naked eye. A muscle, for example, as 
we have already learned, is composed of innumerable filaments, 
visible only by the aid of the microscope ; and the power of 
the muscular mass is but the sum of the contractile power of 
the filaments which enter into its composition. Again, each 
cell of the liver, invisible to unassisted sight, is a secreting 
organ, and the liver performs as much duty as the sum of these 
minute organs renders possible. 

2. The Necessity of the Microscope. — If, therefore, we would 
know the real structure of the human body, we must make use 
of the microscope. Our eyes are constructed for the common 
offices of life, to provide for our wants and guard us from the 
ordinary sources of danger ; but by arming them with lenses, 
the real structure of plants and animals is revealed to our intel- 
ligence; and enemies, otherwise invisible, that lie in wait in 
the air we breathe, and in our daily food and drink, to destroy 
life, are guarded against. 

1. The will of the Creator, by what obeyed ? The power of b muscle ? Amount of duty 
performed by the liver ? 

2. Necessity for using- the microscope ? The advantages gained by its use ? 



334 THE MICROSCOPE 

3. Convex Lenses, or magnifying glasses, are disks of glass 
or other transparent substances, which have the property of 
picturing upon the retina of the eye an image of an object 
larger than the image produced there without their aid. The 
glasses used in microscopes are either double convex lenses (a) 
or plano-convex lenses (b). If either of these lenses be placed 
over a hole in the shutter of a darkened room, or ever the key- 
hole of a door, and a piece of paper be held at a proper dis- 
tance, a picture of all objects in front of the lens will be thrown 
on the paper, as in the camera-obscura or the magic-lantern. 
Now, in the same manner, a lens throws a picture of objects 
to which it is directed on the retina of the eye, and when that 




Fig. 76 

picture is larger than the image made in the eye by the object 
without the aid of the lens, it is magnified, or the lens has 
served as a microscope, so called from its use in seeing small 
objects, from mikros, small, and skopeo, to see. 

4. Different Kinds of Microscopes. — Microscopes are either 
simple or compound. The glasses of magnifying spectacles, 
like those commonly used by aged persons, are simple micro- 
scopes. Magnifying glasses, mounted in frames, such as are 
for sale by opticians and others for the detection of counter- 
feit money, are simple microscopes, and are useful in studying 
the coarser structure of plants and animals. 

5. The most powerful simple microscopes are made by melt- 
ing in a flame a thread of spun glass, so as to form a minute 

3. What are convex lenses ? Kind of lenses used in microscopes ? Experiment ? 
Picture thrown upon the eyes ? Derivation of the word microscope ? 

4. Kinds of microscopes ? What are simple microscopes ? 

5. Construction of the most powerful simple microscopes ? In practice? A doublet? 
Triplet ? Why are compound microscopes superior to simple ones ? 



THE MICROSCOPE 



335 



globule or bead, which, when set in a piece of metal and used 
to examine objects on a plate of glass held up to the light, 
gives a high magnifying power. In practice, however, it is 
found better to use several magnifying glasses of moderate 
power than a simple lens alone of high power. A combination 
of two lenses is called a doublet — of three, a triplet. All sim- 
ple microscopes throw an enlarged image of the object upon 
the retina. Compound microscopes are so constructed that the 
enlarged image of an object is again magnified by a second 
lens, and hence their magnifying power is vastly superior to 
that of simple microscopes. 

6. The accompanying diagrams will explain the action of 
the compound microscope compared with that of the simple 
microscope. In Fig. 77, which represents the working of the 
simple microscope, the rays from the object (a b), passing 
through the lens (l), form an image (a b') in the retina of the 
eye (e), and as all images are inverted in the eye, the object is 




Fig. 77. —Simple Microscope 

seen as all other objects are, and appears erect. In Fig. 78 is 
seen the action of the compound microscope. An inverted 
image (a' b') of the object (a b) is magnified by the second Ions 
(l'), and an erect image is thrown upon the retina, which, as 
all other objects seen erect with the naked eve are inverted, 
gives to the image a contrary direction, or inverts it to the 
mind. 

7. A Compound Microscope consists of two portions: the 
optical portion, or the lenses, and the mechanical portion, or 
the instrument which bears the lenses. The glasses of a com- 



o. Explain, by means of the diagram, tin* action of the compound microscope, 
'(. Portions, in a compound ! licroscope? The glasses? 



336 



THE MICROSCOPE 



pound microscope are two : the object-glass and the lower lens 
of Fig. 78, and the ocular or eye-piece and the upper piece of 
Fig. 78. Both the object-glass and the eye-piece may, and 
usually do, consist of more than one lens, for, as has been pre- 
viously mentioned, better results are obtained by a combina- 
tion of lenses of moderate power than by o^l>q 
single lenses of high power and great curva- 
ture. 

8. How to Choose and Use a Microscope. — 

No attractiveness in the mechanical part of 
a microscope can compensate for inferior 
lenses ; and the very first consideration in 
the choice of an instrument should be the 
excellence of the optical part of the instru- 
ment. In the use of the instrument, care 
should be exercised to keep the lenses clean, 
free from dust, not to press the object-glass 
upon the object under observation, and not 
to wet it in the water in which most objects 
are examined. A good microscope requires 
its own table ; and when not in use, should 
be covered by a bell glass, or a clean linen 
cloth. 

9. The mechanical portion of the instru- 
ment varies greatly in different instruments. 
That one is the best which is the simplest, 
the most solid and most easily managed. 
Most objects in human anatomy are exam- 
ined in water or in other liquids, or they are 
themselves liquids ; hence an oblique stage 
is often inconvenient. 



10. Additional Apparatus. — As almost all 
objects in human anatomy are examined by 
transmitted light thrown up from the mir- 




Fig. 78. — Compound 
Microscope 



8. How to choose a microscope ? How to use it ? 

9. The characteristics of the best instrument? What special requisites should be 
insisted upon ? Why, as to a horizontal stage ? 

10. Slides? Covers, square and circular ? How kept ? 



THE MICROSCOPE 337 

ror beneath the stage through the object to the eye, they must 
be placed upon strips of clear glass about three inches long 
and one inch wide, commonly called " slides." These should 
be procured with the microscope. Again, most objects seen 
with high powers require to be covered with a thin plate of 
glass, very properly called a " cover," that the moisture of the 
specimen may not tarnish the object-glass. Square or circular 
covers of very thin glass are therefore provided ; and a good 
supply of these should be always on hand. These glasses 
should be kept in a. covered dish filled with a mixture of alco- 
hol and water. Simple water will not remove the fatty matter 
which exists in all animal tissues, and, therefore, the glasses 
cannot be thoroughly cleaned with it alone. 

11. When glasses are required for use, they should be 
removed from the liquid and wiped clean and dry with a soft 
linen handkerchief. Delicate knives, scissors, needles mounted 
in handles, forceps, pipettes or little tubes for taking up water, 
should be obtained; these are essential to all microscopical 
study. The table should be supplied with glass-stoppered 
bottles containing the various liquids ordinarily used in the 
study of physiology. Thus, tincture of iodine is indispensable 
in studying vegetable structure, acetic acid in the study of 
animal tissues ; and other articles will have to be added from 
time to time, as your progress in study demands them. 

12. Preliminary Studies. — In order to prepare the way for 
the study of any department of science with the aid of the 
microscope — for the microscope is but an eye, and can be 
turned in almost any direction for purposes of investigation 
— it is necessary to become acquainted with the many objects 
which are liable to complicate the examination of particular 
structures. Both air and water arc 4 full of floating bodies, 
and the most common of these should first occupy the atten- 
tion. In the city, particles of starch arc always floating in the 
air. Take a very minute portion of wheat flour, place it in the 
middle of a clean glass "slide," drop upon it a drop o{ pure 



11. Cleaning the glasses ? Knives, soissors, etc f Various liquids ? 

12. Bodies, in air and water V Tho examination of starch ? 



338 THE MICROSCOPE 

water, cover it with a plate of thin glass, and examine it with 
a power of from one hundred to six hundred diameters. It 
will be found to be composed of minute grains or granules, the 
largest of which are made up of coats or layers, like an onion, 
arranged around a central spot called the hilum. 

13. Make another preparation in the same manner, and, 
after adding the water and before covering with the thin glass 
cover, add a small drop of a solution of iodine. Now, upon 
examining the specimen, every grain will be seen to be of a 
beautiful deep blue color. After thus studying wheat starch, 
the starch of Indian corn, of arrow-root, and of various grains, 
should be examined in like manner, and their resemblances 
and differences noted. The granules of potato-starch are as 
distinctly marked as any. 

14. Fibres of cotton, lint, and wool are liable to be found in 
every specimen prepared for microscopical examination. In 
order to study these, any cotton, woollen, or linen fabric 
or garment, may be scraped, and the scrapings placed on 
a piece of glass moistened with water, covered with the thin 
glass plate or cover as before, and examined with the same 
magnifying power, namely, from one hundred to six hun- 
dred diameters. Vegetable hairs or down are constantly 
floating in air and water. These are of very various forms, 
are simple or grouped, and form very interesting objects of 
study. They are readily procured from the epidermis or outer 
membrane of the leaves or stems of plants, by cutting with a 
delicate knife. 

15. The tissues of plants, epidermis, ducts, and woody fibres 
are constantly found in microscopic preparations. They may 
be studied in delicate sections made with a sharp knife, or by 
tearing vegetable tissues apart with needles. The down of 
moths, the hairs of different animals, the fibres of paper, the 
most common animalcules in water, the dust of shelves, and 
generally the structures found in all vegetable and animal sub- 



13. The examination with solution of iodine ? Advice respecting other articles ? 

14. Directions for examining- cotton and other fibres ? Vegetable hairs ? 

15. Directions for examining various tissues ? Down of moths and other structure 



THE MICROSCOPE 339 

stances by which we are surrounded, should be studied as a 
preliminary to any special line of microscopical investigation. 

16. The Study of Human Tissues. — When this has been done 
and familiarity with the use of the instrument has been ob- 
tained, proceed to the study of the human body, for human 
physiology is our subject. If the end of the finger be pricked 
with a pin, a drop of blood may be procured for examination. 
Place this on one of the glass slides, cover it with a thin piece 
of glass, press down the cover so as to make a thin layer, and 
then examine with the magnifying power just mentioned. Do 
not add water, for that will cause the blood corpuscles to dis- 
appear. If the drop of blood is placed under the microscope 
at once after being drawn from the finger, most interesting 
phenomena will be observed. The red corpuscles will be seen 
to arrange themselves in rows, like piles of coin, while the 
blood is coagulating. The spherical, white corpuscles will be 
left out of the rows of red discs, and, if the highest power be 
used, will be seen to change their shape constantly. 

17. If you scrape with a dull knife the inside of the cheek, 
the flattened scales of " pavement epithelium," or of the 
insensible covering which, analogous to the scarf-skin on the 
outer surface of the body, lines the cavities of its interior, 
may be readily studied. They have the appearance of trans- 
parent tiles, each enclosing a round or oval body, called its 
nucleus. Dandruff and the scrapings from the skin of the 
body are composed of scales like those of the mouth, but they 
differ somewhat in being hardened by horny matter, and in 
having a very faint central body or nucleus. 

18. The Tissues of the Inferior Animals. — The warm-blooded 

animals do not differ in the tissues or microscopic structures 
that compose them, but only in the amount and arrangement 
of these tissues. Milne-Edwards says these tissues "do not 
differ much in different animals, but their mode oi' association 



16. Directions for examining a drop of blood ? 
IT. Examination of the scales of the mouth ? Dandruff J 

IS. In what, as respects the tissues, do the warm-blooded animals differ v Statement 
>f Milne-Kd wards ? 



340 THE MICROSCOPE 

varies, and it is chiefly by reason of the differences in the com- 
bination of these associations in various degrees, that each 
species possesses the anatomical properties and characters 
which are peculiar to it." 

19. Hence the butcher's stall will furnish all the materials 
for the study of the microscopic tissues. The structure of the 
heart, lungs, liver, brain, and muscle, may all be studied, and 
well studied, by using minute pieces of the flesh of the lower 
animals, especially of the quadrupeds. Such portions of these 
animals as are not exposed for sale can be readily obtained by 
order from the slaughter-house. To examine with the powers 
of which we have been speaking, it is only necessary to cut off 
exceedingly small pieces, tear them apart with needles, or make 
very delicate sections with a sharp knife. 

20. Incentives to Study. — A complete knowledge of all 
minute structures is not to be expected at once, for you are 
here introduced into a new realm of Nature, a world of little 
things as vast, as wonderful, and as carefully constructed as 
the starry firmament — that other realm of grand objects which 
the astronomer rightly scans with the telescope. It will not 
appear singular, therefore, if, at first, you feel strange and 
awkward in this new creation. With a little perseverance, 
however, and with the attention directed towards simple ob- 
jects at the outset, it will not be long before an increasing 
experience will engender confidence. 

21. If to all this there be added an enthusiastic study of 
the standard authorities on the subject, the rate of progress 
will be much more rapid. As compared with similar studies, 
few possess more interest than microscopy, and to the one who 
pursues it with fondness, it constantly affords sources of pleas- 
ure and agreeable surprises ; and in the end often deads to new 
and valuable additions to the sum of human knowledge. The 
depths which the microscope is employed to fathom are no 
more completely known than are the heights above us explored 
and comprehended by the astronomer. 

19. How to procure materials for the study of the tissues of man ? 

20, Incentives to study ? U, How may the rate of progress be increased ? 



THE MICROSCOPE 341 



QUESTIONS FOR TOPICAL REVIEW 

PAGB 

1. Say what you can of the law of the tissues 333 

2. What, then, is the necessity of the microscope ? 333 

3. Define and state use of convex lenses 334 

4. Name some of the kinds of microscopes 334, 335 

5. Explain action of compound microscope 335 

6. Of what parts does it consist ? 335, 336 

7. What parts are of most importance ? , 336 

8. How would you prepare specimens ? 330, 337 

9. What further directions are given ? 337 

10. What is said of preliminary studies ? 337-338 

11. Give statement regarding study of human tissues 339 

12. Tissues of inferior animals 339, 340 



CHAPTER XIII 

FIRST HELP IN ACCIDENTS 

1. Shock. — The term shock is applied to a condition of more 
or less severe prostration, the result of some severe injury, 
accident, or fright. It may or may not be accompanied by 
loss of consciousness. The part affected is the nervous sys- 
tem at large, and hence almost all the organs in the body suffer 
more or less. Persons are differently affected by the same 
injury; in some, a comparatively slight accident produces a 
profound degree of shock, and in others, a severe injury only 
a very slight degree. The lighter forms of shock usually pass 
off in a short while, but in the severer forms a person may die 
without any injury being present. A person suffering from 
shock will be found completely prostrated, unable to stand, his 
body limp, face pale and anxious, covered with cold perspira- 
tion, respiration feeble and shallow, pulse either very feeble 
or imperceptible, and he may be conscious or unconscious. 

The great danger to this person lies in heart failure, and 
if the shock is profound, death may ensue, unless help 
is promptly given. Much can be done before medical aid 
arrives, and a life may be saved by prompt action. As the 
heart is the chief organ affected through the nervous system, 
everything to promote its action should be done. Place the 
sufferer flat upon his back, with the head low ; loosen all tight 
clothing about the neck and chest ; give whiskey or brandy in 
hot water in small doses at intervals of fifteen minutes or 
half an hour ; surround the body with hot-water bottles, and 
keep the patient warm and quiet. 

2. Fainting. — This is the result of deficiency of blood in 
the brain. Some people, especially women, faint very easily ; 

1. Shock, its causes and symptoms ? Danger? Treatment? 

2. Fainting, its causes and treatment ? 

312 



FIRST HELP IN ACCIDENTS 



343 



the sight of blood or surgical instruments, a gruesome story, 
the recital of an accident, are sufficient causes. As a rule, the 
faint is of short duration, and all that is necessary is to place 
the person upon the back, with the head low ; loosen all cloth- 
ing about the neck and chest ; open a window to admit fresh air, 
and sprinkle the face with cold water. If the faint occurs at 
church or at some public gathering, remove the person promptly 
to the outer air ; for foul air is frequently the cause of the 
trouble. If after the above means have been emrjloyed a 
person does not regain consciousness, give small doses (tea- 
spoonful) of whiskey and water, equal parts, and if that is not 
sufficient, elevate the legs and body, so as to promote as much 
as possible the flow of blood to the brain. 

3. Vertigo. — This is "a rush of blood to the brain." The 
body should be placed in a sitting posture, with the head erect. 
If the blood escapes into the brain by reason of the rupture of 
a blood-vessel within it, the case is very grave, and the physi- 
cian should be summoned at once. Meanwhile, let the position 
be as above stated. Apoplexy is known, in very many cases, 
by the helpless condition of an arm or leg, or both. 

4. Hemorrhage, or Bleeding. — There is no doubt that many 
a life has been lost, from severe hemorrhage, which could have 

been saved, had intelligent aid been at 
hand to stop the bleeding-point. As a 
rule, the bleeding of a small wound, 
although profuse, can be readily con- 
trolled by firm pressure over it, or by 
tying a strip of bandage round it ; but 
in the severer forms of hemorrhage, 
where large vessels are torn or cut, 
this is not so easily accomplished. 
Learn the difference between the two 
kinds of bleeding, "arterial" and "ve- 
nous." Arterial is bright red, and comes 
in jets (or throbs corresponding to the 




8. Vertigo, its treatment? Apoplexy, how known ? 
4. Hemorrhage, or Bleeding, its treatment 1 Difference between 
venous " bleeding J Treatment of each? Outfit for every household? 



arterial" ami 



344 



FIBST HELP IX ACCIDENTS 



pulse) ; venous is dark-colored, and flows continuously. If a 
larger vessel of the arm or leg lias been injured, and cannot be 
controlled by direct pressure, tie a 
cord or handkerchief loosely around 
the limb away from the wound on 
the side nearest the heart, put a 
stick through it and twist until the 
bleeding stops. In addition to this, 
tie a pad firmly on the wound. Loss 
of blood "from arteries is apt to be 
more rapid and dangerous than that 
from veins, and when the cut vessel 
is a large one. the skill of the sur- 
geon will ordinarily be required in 
order to close the bleeding artery 
permanently and securely. 

It is well, in every household, to 
have, in some handy and well-known 
place, some strips of old muslin and 
some lint, or oakum, a bandage or 
two, and some adhesive plaster, a soft sponge, and needles and 
thread in a basket or box by themselves. In this way. valu- 
able time may be saved in the staunching of blood, flowing in 
consequence of some accidental cut or other injury. 

5. Fractures and Dislocations. — A broken bone in surgical 
language is called a fracture : a bone out of its joint is called 
a dislocation. When, in addition to the fracture, there is pre- 
sent a laceration of the soft parts surrounding it, the muscles 
and the skin, so that the broken end of a bone protrudes 
through the latter, we speak of it as a compound fracture. The 
symptoms of a fracture are: pain and inability to move the 
affected limb ; there will be mobility at the point of the frac- 
ture, and the broken ends of the bone may be felt to grate 
upon each other ; if the leg be broken at any point the patient 
will be unable to stand upon it. 

The symptoms of a dislocation are : altered shape of the 




Fig. 80 



5. Describe a fracture : a dislocation : a compound fracture; symptoms of each. What 
can he done lor each, pending the arrival of surgical aid ? 



FIRST HELP IN ACCIDENTS 



345 



limb; inability to move it; great pain in and about the joint 
upon the slightest attempt at motion. 

Much can be done for the comfort of a patient, pending the 
arrival of surgical aid. First of all, remember that a person 
with a broken bone may, without suffering harm, wait several 
hours and even a day for the so-called " setting " of the bone. 
Rest and support of the injured member are the two things to 
be accomplished. First remove all clothing from ^the arm or 
leg, best by slitting the garments open, and not by pulling 
them off ; then firmly tie a strip of wood on either side of the 
limb, protecting the skin by padding the wood well with any- 
thing soft, cotton, pieces of clothing, etc. . A good support is 
given by tying a pillow firmly around the arm or leg. In 




Fig. 81 

moving a person suffering from a fractured leg or arm, some 
one should carry the broken limb carefully and evenly, so as 
to avoid all jarring and all motion at the seat of the fracture, 
which would be extremely painful. Should some hours have 
to elapse before the surgeon arrives, the limb should be in- 
spected from time to time to see that the cords are not tied too 
tightly, for considerable swelling follows each fracture. 

The help in dislocations lies chiefly in the proper support of 
the limb in the position in which it is found. In moving 
a person suffering from a dislocation, let one person support 
the limb, and after the patient is at rest, place it in the posi- 
tion which proves the most comfortable for the sufferer, sup- 
porting it on either side with pillows, stones, or pieces o( wood. 
('old water compresses to the joint, if there is much pain, will 
feel most grateful. 



346 FIRST HELP IN ACCIDENTS 

6. Sprains. — A sprain is a severe straining or tearing of 
the ligaments surrounding a joint. In the milder forms these 
are only greatly stretched, but in the more severe cases they 
are torn entire or in part, in some cases being even complicated 
by a tearing off or breaking of the ends of the bones forming 
the joint. Every joint may suffer from a sprain, although it 
is most frequently met with in the ankle. 

The symptoms of a sprain are : severe pain in the affected 
joint, both upon motion and at rest; swelling sets in usually 
soon after the receipt of the injury, and blood soon makes its 
appearance under the skin, coming from the ruptured blood- 
vessels. 

The best immediate relief that can be given is to place the 
joint in hot water, as hot as can be borne, and keep it there 
for several hours, or until the doctor arrives, adding hot water 
as it cools. Should medical aid not be obtainable, then take 
the limb out of the hot water after two hours, and bandage it 
firmly, well below and above the joint, so as to give the great- 
est support and prevent all motion. 

7. Burns and Scalds. — The secret of the best treatment of 
these injuries is to exclude the air from the wounded surfaces. 
When they are slight, and the skin is not destroyed, but merely 
blistered, prevent the displacement of the skin as much as 
possible. Let the blisters be punctured, if necessary, to let 
out the liquid, and then keep the skin in place by cotton cloth 
or lint, wet with a solution of one teaspoonful of carbolic acid 
in a quart of water, or a strong solution of baking soda. The 
cloth should be kept wet constantly, but do not irritate the 
wound by taking off the dressing too often. 

Extensive burns are much worse than deep burns. In the 
former case, the outlook is grave, and the patient will probably 
require the best aid, both medical and surgical, of some 
physician. 

Scars after Burns. — If a burn be on the face, neck, or near 

G. Sprains, description, symptoms, immediate relief? How treated if medical aid is not 
obtainable ? 

7. Burns and scalds, best treatment? What are tbe worst burns ? What about scars ? 
Spontaneous combustion ? What should be done when a woman's clothes are on fire ? 



FIRST HELP IN ACCIDENTS 347 

a joint, it is not well to hasten the healing process, on account 
of the contraction that always takes place as the scar is formed. 
" Fire is a source of danger, and is very destructive to life 
at times. Spontaneous combustion of the human body when 
saturated with alcohol is a myth, though perhaps the alcohol- 
ized body does burn more readily than one free from inflam- 
mable fluid. When a lady is on fire, she should not and 
ought not to be permitted to run ; that fans the flames 
amazingly. She must be laid down and rolled up in the 
nearest woollen article, — rug, coat, or blanket. Such wrap- 
ping up in a non-inflammable article is a most effective method 
of extinguishing the flames. Immersion in water is, unfortu- 
nately, rarely practicable." — Fothergill. 

8. Illuminating Gas is dangerous in two ways. If it escapes 
into a tightly closed room in sufficient quantities, it causes the 
death of the inmates by suffocation, unless some one from 
without discovers the perilous situation. If not too late, 
remove the patient into fresh air, undo the clothing, dash cold 
water on the face and neck, and employ artificial respiration, 
as in drowning (see p. 336). Again : If it escapes freely into 
an apartment, it forms an explosive compound by mixing with 
the air. If then a light is unguardedly taken into the place, 
an explosion that may be destructive to life will result. 
Always thoroughly air any room that has the odor of escaping 
gas before a light is taken in. 

9. Kerosene is the cause of even more " accidents " than gas. 
Too much care cannot be taken in its use. Buy only that 
which has been tested, but remember that not all that are 
marked as " safe " are truly so. If a responsible oil-man certi- 
fies that the oil will not "flash " under 140 degrees, it may be 
regarded as safe if properly used. Lamps should be filled only 
in the daytime. Never attempt to fill a lamp that is lighted, 
and never put kerosene in the stove for the purpose oi' kindling 
a fire. Very small lamps are dangerous, as also is a lamp that 
has burned a long time, and has but very little oil in it. 



8. Illuminating gas, In what two ways dangerous? 

9. Kerosene, what kind to use? Cautions to be observed in using? 



348 FIRST HELP IN ACCIDENTS 

10. Frost-bites. — Keep away from the fire and in a cool 
room. Rub the nose, or other part that has been " bitten," with 
snow or ice-water until the blood is warmed again and circulat- 
ing in the part. Chilblains should not be brought to the tire : 
if the skin is unbroken, it should be hardened by brushing it 
over with alcohol having tannin in it. 

11. Sunstroke is seldom produced in this climate in persons 
who have not labored too hard. Fatigue and sun-heat are 
commonly the joint causes of sudden prostration in summer ; 
although "heat-stroke" may occur in an artificially heated 
atmosphere, without exposure to the sun. In the tropics, the 
least possible exertion is put forth by the natives during the 
midday hours. On very hot days, therefore, avoid fatigue and 
open-air labor as much as possible. Keep the head cool. If 
any unusual, dizzy feeling comes on, apply cold water to the 
head and neck. If a person falls unconscious, and the skin 
is decidedly hot and dry, he should be taken to a cool place. 
If the face and head are red and hot, apply ice-water on 
cloths. If pale, give stimulants gradually, and use cold water 
sparingly. 

12. Fits or Convulsions. — These may be trivial or grave. 
If the patient is a young woman, the attack is probably hyster- 
ical, and, as a rule, not dangerous, and a sprinkle of cold water 
will bring relief. If the patient struggles with regularity of 
movement, and there is bloody froth on the lips, it is a case of 
epilepsy, and requires a physician's attendance. Meanwhile, 
protect the head from injury by putting a pillow or some soft 
article beneath it; a cork introduced between the teeth will 
prevent the biting of the tongue. Prevent the person from 
falling or injuring himself, but do not attempt to forcibly hold 
him quiet. 

In children apply cloths dipped in water to the head ; disturb 
the child as little as possible; do not use a warm bath until 
directed by the doctor. 

10. Frost-bites and chilblains,treatment of each ? 

11. Sunstroke, causes ? Precautions against? Treatment? 

12. Fits or convulsions, kinds of? Treatment of each ? 



FIRST HELP IN ACCIDENTS 349 

13. Drowning. — Marshall Hall's" Beady Method" of treat- 
ment in asphyxia from drowning, chloroform, coal-gas, etc. 

1st. Treat the patient instantly on the spot, in the open air, 
freely exposing the face, neck, and chest to the breeze, except 
in severe weather. 

2d. In order to clear the throat, place the patient gently on 
the face, with one wrist under the forehead, that all fluid, and 
the tongue itself, may fall forward, and leave the entrance into 
the windpipe free. 

3d. To excite respiration, turn the patient .slightly on his 
side, and apply some irritating or stimulating agent to the 
nostrils, as veratrine, dilute ammonia, etc. 

4th. Make the face warm by brisk friction ; then dash cold 
water upon it. 

5th. If not successful, lose no time ; but, to imitate respira- 
tion, place the patient on his face, and turn the body gently, 
but completely, on the side, and a little beyond; then again on 
the face, and so on, alternately. Repeat these movements 
deliberately and perseveringly, fifteen times only in a minute. 
(When the patient lies on the thorax, this cavity is compressed 
by the weight of the body, and expiration takes place. When 
he is turned on the side, this pressure is removed, and inspira- 
tion occurs.) 

6th. When the prone position is resumed, make a uniform 
and efficient pressure along the spine, removing the pressure 
immediately, before rotation on the side. (The pressure aug- 
ments the expiration, the rotation commences inspiration.) 
Continue these measures. 

7th. Rub the limbs upward, with firm pressure, and with 
energy. (The object being to aid the return of venous blood 
to the heart.) 

8th. Substitute for the patient's wet clothing, it' possible. 
such other covering as can be instantly procured, each 
bystander supplying a coat or cloak, etc. Meantime, and 
from time to time, to excite inspiration, let the surface of the 
body be slapped briskly with the hand. 



IS. Drowning. What is Hull's ready method of treatment in asphyxia lVoin drowning. 
chloroform, coal-pas, etc. ? 



350 FIRST HELP IN ACCIDENTS 

9th. Rub the body briskly until it is dry and warm, then 
dash cold water upon it, and repeat the rubbing. 

Avoid the immediate removal of the patient, as it involves a 
dangerous loss of time; also, the use of bellows, or any forcing 
instrument ; also, the warm bath, and all rough treatment. 

14. Poisons and their Antidotes. — Accidents from poisoning 
are of such frequent occurrence, that every one should be able 
to administer the more common antidotes, until the services of 
a physician can be obtained. As many poisons bear a close 
resemblance to articles in common use, no dangerous substance 
should be brought into the household without having the word 
poison plainly written or printed on the label ; and any pack- 
age, box, or vial, without a label, should be at once destroyed, 
if the contents are not positively known. 

When a healthy person is taken severely and suddenly ill 
soon after some substance has been swallowed, we may suspect 
that he has been poisoned. In all cases where poison has been 
taken into the stomach, it should be quickly and thoroughly 
expelled by some active emetic, which can be speedily ob- 
tained. This may be accomplished by drinking a tumblerful 
of warm water, containing either a tablespoonful of powdered 
mustard or of common salt, or two teaspoonfuls of powdered 
alum in two tablespoonfuls of syrup. When vomiting has 
already taken place, it should be continued by copious draughts 
of warm water or mucilaginous drinks, such as gum-water or 
flaxseed tea, and tickling the throat with the finger until there 
is reason to believe that all the poisonous substance has been 
expelled from the stomach. 

The following list embraces only the more common poisons, 
together with such antidotes as are usually at hand, to be used 
until the physician arrives : — 

Acids. — Hydrochloric acid ; muriatic acid (spirits of salt) ; 
nitric acid (aqua fortis) ; sulphuric acid (oil of vitriol). 

Antidote. — An antidote should be given at once to neutral- 
ize the acid. Strong soapsuds is an efficient remedy, and can 
always be obtained. It should be followed by copious draughts 



14. Give class, character, and antidote of each poison mentioned above : 



FIRST HELP IN ACCIDENTS 351 

of warm water or flaxseed tea. Chalk, magnesia, soda, or sale- 
ratus (with water), or lime-water are the best remedies. When 
sulphuric acid has been taken, water should be given sparingly, 
because, when water unites with this acid intense heat is pro- 
duced. 

Oxalic acid. 

Antidote. — Oxalic acid resembles Epsom salts in appear- 
ance, and may easily be mistaken for it. The antidotes are 
magnesia, or chalk mixed with water. 

Prussic acid ; oil of bitter almonds ; laurel ivater ; cyanide 
of potassium (used in electrotyping). 

Antidote. — Cold douche to the spine. Chlorine water, or 
water of ammonia largely diluted, should be given, and the 
vapor arising from them may be inhaled. 

Akalies and their Salts. — Ammonia (hartshorn), liquor or 
ivater of ammonia. Potassa: — caustic potash, strong lye, car- 
bonate of potassa (pearlash), nitrate of potassa (saltpetre). 

Antidote. — Give the vegetable acids diluted, as weak vine- 
gar, acetic, citric, or tartaric acids dissolved in water. Castor 
oil, linseed oil, and sweet oil may also be used ; they form 
soaps when mixed with the free alkalies, which they thus 
render harmless. The poisonous effects of saltpetre must be 
counteracted by taking mucilaginous drinks freely, so as to 
produce vomiting. 

Alcohol. — Brandy, wine ; all spirituous liquors. 

Antidote. — Give as an emetic ground mustard or tartar 
emetic. If the patient cannot swallow, introduce a stomach 
pump ; pour cold water on the head. 

Gases. — Chlorine, carbonic acid gas, carbonic oxide, funics of 
burning charcoal, sulphuretted hydrogen, illuminating or coal gas. 

Antidote. — For poisoning by chlorine, inhale, cautiously, 
ammonia (hartshorn). For the other gases, cold water should 
be poured upon the head, and stimulants cautiously adminis- 
tered; artificial respiration. (See Marshall HalVs Heady 
Method, page 336.) 

Metals. — Antimony, tartar emetic, trine of antimony, etc. 

Antidote. — If vomiting has not occurred, it should be pro- 
duced by tickling the- throat with the finger or a feather, and 



352 FIRST HELP IX ACCIDENTS 

the abundant use of warm water. Astringent infusions, such 
as common tea, oak bark, and a solution of tannin, act as 
antidotes. 

Arsenic. — White arsenic, Fowler's solution, fly powder, cobalt, 
Paris green, etc. 

Antidote. — Produce vomiting at once with a tablespoonf ul 
or two of powdered mustard in a glass of warm water, or with 
ipecac. The antidote is hydrated peroxide of iron. If Fow- 
ler's solution has been taken, lime-water must be given. 

Copper. — Acetate of copper (verdigris), sulphate of copper 
(blue vitriol), food cooked in dirty copper vessels, or pickles 
made green by copper. 

Antidote. — Milk or white of eggs, with mucilaginous 
drinks (flaxseed tea, etc.), should be freely given. 

Iron. — Sulphate of iron (copperas), etc. 

Antidote. — Carbonate of soda in some mucilaginous drink, 
or in water, is an excellent antidote. 

Lead. — Acetate of lead (sugar of lead), carbonate of lead 
(white lead), water kept in leaden pipes or vessels, food cooked 
in vessels glazed with lead. 

Antidote. — Induce vomiting with ground mustard or com- 
mon salt in warm water. The antidote for soluble prepara- 
tions of lead is Epsom salts ; for the insoluble forms, sulphuric 
acid largely diluted. 

Mercury. — Bi-chloride of mercury (corrosive sublimate), 
ammoniated mercury (white precipitate), red oxide of mercury 
(red precipitate), red sulphuret f mercury (vermilion). 

Antidote. — The white of eggs, or wheat flour beaten up 
with water and milk, are the best antidotes. 

Silver. — Nitrate of silver (lunar caustic). 

Antidote. — Give a teaspoonful of common salt in a 
tumbler of water. It decomposes the salts of silver and 
destroys their activity. 

Zinc. — Sulpjhate of zinc, etc. (white vitriol). 

Antidote. — The vomiting may be relieved by copious 
draughts of warm water. The antidote is carbonate of soda 
administered in water. 

Narcotic Poisons. — Opium (laudanum, paregoric, salts of 



FIRST HELP IN ACCIDENTS 353 

morphia, Godfrey's cordial, Dalby's carminative, soothing 
syrup, cholera mixtures), aconite, belladonna, hemlock, stra- 
monium, digitalis, tobacco, hyosciamus, nux vomica, strychnine. 

Antidote. — Evacuate the stomach by the most active emet- 
ics, as mustard, alum, or sulphate of zinc. The patient should 
be kept in motion, and cold water dashed on the head and 
shoulders. Strong coffee must be given. The physician will 
use the stomach pump and electricity. In poisoning by nux 
vomica or strychnine, etc., chloroform or ether should be in- 
haled to quiet the spasms. 

Irritant Vegetable Poisons. — Croton oil, oil of savine, poke, 
oil of tansy, etc. 

Antidote. — If vomiting has taken place, it may be ren- 
dered easier by copious draughts of warm water. But if 
symptoms of insensibility have come on without vomiting, it 
ought to be immediately excited by ground mustard mixed 
with warm water, or some other active emetic, and after its 
operation an active purgative should be given. After evacuat- 
ing as much of the poison as possible, strong coffee or vinegar 
and water may be given with advantage. 

Poisonous Fish. — Conger eel, mussels, crabs, etc. 

Antidote. — Evacuate, as soon as possible, the contents of 
the stomach and bowels by emetics (ground mustard mixed 
with warm water or powdered alum) and castor oil, drinking 
freely at the same time of vinegar and water. Ether, with 
a few drops of laudanum mixed with sugar and water, may 
afterward be taken freely. 

Poisonous Serpents. — Antidote. — A ligature or handker- 
chief should be applied moderately tight above the bite, and 
a cupping-glass over the wound. The patient should drink 
freely of alcoholic stimulants containing a small quantity of 
ammonia. The physician may inject ammonia, into the veins. 

Poisonous Insects. — Stings of scorpion, hornet, icasj). bee, etc. 

Antidote. — A piece of rag moistened with a solution of 
carbolic acid may be kept on the affected part until the pain 
is relieved; and a few drops of carbolic acid may be given 
frequently in a little water. The sting may be removed l\v 
making strong pressure around it with the barrel oi' a small 
watch-key. 



354 FIRST HELP IN ACCIDENTS 



QUESTIONS FOR TOPICAL REVIEW 

PAGE 

1. What is a frequent accompaniment of severe accidents ? 342 

2. What would you do for a person suffering from shock ? from faint- 

ness ? from vertigo ? 342, 343 

3. How would you recognize and check arterial bleeding ? 343, 344 

4. What is the difference between a fracture and a dislocation ? 344, 345 

5. What can you do for each until a physician arrives ? 345 

6. What are the causes, symptoms, and treatment of a sprain? 346 

7. What is the treatment for burns and scalds ? 346, 347 

8. What is the treatment for asphyxia from inhaling illuminating gas ? 347 

9. What is the best thing to do when your nose or ears are frost-bitten ? 348 

10. What are the signs of sunstroke, and what would you do for any 

one suffering from it ? 348 

11. What is said about fits and convulsions ? 348 

12. Give a careful account of the way to treat a person apparently 

drowned ? 349, 350 

13. Take up each of the poisons mentioned and give its antidote 350, 354 



CHAPTER XIV 

BACTERIA AND DISEASE 

Bacteria — Cause Disease — Require Warmth and Moisture — Varieties 
of Bacteria — Toxines and Ptomaines — Antitoxine — Destruction of 
Bacteria 

1. Bacteria. — The term bacteria is applied to a large num- 
ber of microscopic organisms, found both in the animal and 
vegetable kingdoms. In shape they are spherical, oval, rod- 
like, or spiral, and their size varies from 2 5F0 o" *° roioo °^ an 
inch in breadth, and from 2W0 to T2V0 °^ an mca m length. 
They obtain their nourishment entirely from organic matter, 
which they destroy during the continuance of their lives. 
They are divided into saprophytes and parasites ; the former 
obtaining their nutrition from dead organic matter, and the 
latter from living organic matter. Decomposition, putrefaction, 
and fermentation are the results of the action of saprophytic 
bacteria ; the action of parasitic bacteria always results in 
disease. We thus see that bacteria may exercise both benign 
and malignant influences in the processes of life. The processes 
of decomposition which we observe all around us in nature 
should be called benign, because dead animal and vegetable 
matters are thereby transformed into such chemical compounds 
as carbonic acid gas, ammonia, and water, which may again act 
as nourishment for living plants. 

2. Bacteria Cause Disease. — The investigations into the causes 
of various diseases, afflicting both man and animals, have led 
to the discovery of various bacteria as the probable causes ; 



1. What are bacteria ? How do they obtain nourishment ? Into what classes we they 

divided ? What results from their action ? 

2. Bacteria fts the cause of disease ? Mode of propagation 1 

355 



356 BACTERIA AND DISEASE 

and the opinion held by many of the most noted investigators 
to-day is, that all diseases are caused each by its specific bac- 
terium. The great value of this discovery is apparent when 
we consider it in connection with the prevention and cure of 
diseases. 

The mode of propagation of all bacteria is by a process of 
transverse subdivision, not unlike that illustrated in the first 
chapter of this book. 

3. Warmth and Moisture. — All bacteria require for their 
existence both warmth and moisture, so that neither animal 
nor vegetable matter can be decomposed at low temperatures 
or in the absence of moisture. This is well shown by the 
fact that meat may be kept indefinitely in a frozen state. The 
finding of the absolutely preserved body of the Mammoth 
elephant, frozen in the ice of Siberia for thousands of years, 
is a further illustration of the prevention of decay at low tem- 
peratures. The preservation of meat by drying proves the 
absence of decay when no moisture is present. 

4. Yeast and mould are examples of two of the simpler bac- 
teria which are present in the atmosphere at all times ; each 
seeks its own field for nourishment and growth. When yeast 
germs find a liquid containing sugar, a process is set up called 
fermentation. The yeast germs feeding on the sugar convert this 
into alcohol and carbonic acid gas, and being thus nourished, 
rapidly increase in numbers, so that when all the sugar has 
been consumed, and the process of fermentation has ceased, 
we shall find a large increase in the yeast. 

Mould exists in many varieties, and may be observed in 
various colors and modes of growth on decaying vegetable 
matters. 

5. If we begin now the consideration of the disease-produc- 
ing bacteria, we are confronted by a field so vast that even an 
outline description cannot be given in a work of this kind. 
The three main divisions of bacteria have received the names 
of micrococci, bacilli, and spirilla. The micrococci comprise 

3. Warmth and moisture ? Illustrate the principle. The Mammoth elephant? 

4. Yeast and mould ? Fermentation ? 

5. The three main divisions of bacteria? 



BACTERIA AND DISEASE 357 

all those of a spherical form, the bacilli are all oval or rod- 
like, and the spirilla are either curved or twisted. The mode 
of entrance of these various bacteria into the human body 
may be by either air or by food. Bacteria, in order to produce 
disease, must find an entrance into the tissues of the body in 
some way. By inhalation, they would be deposited in the 
mouth or nose, or in some other part of the respiratory tract ; 
by food, they could gain entrance to the mouth, the stomach, 
or the intestines. In contagious diseases, the propagation 
would be either through breathing the atmosphere of the sick- 
room or through personal contact, in which case the contagion 
is probably conveyed by the hands to the mouth. 

6. Toxines and Ptomaines. — As soon as the bacteria gain 
entrance to the human body in any of the above enumerated 
ways, and find a proper surface for their development, they 
live upon the albumen of the tissues which they inhabit. 
Here again, as shown in the yeast example, a rapid propaga- 
tion takes place, and consequently a rapid spreading into 
adjacent, and even far distant, parts of the body. Their 
growth in the living tissues of the human body results in the 
production of poisonous substances, called toxines and pto- 
maines ; to these the symptoms of disease are ascribed. 

7. Antitoxine. — After certain of the bacterial diseases have 
run their course, and the patient has recovered, there seems to 
be established in the body the power to resist future attacks, 
as, for instance, in cases of typhoid fever, smallpox, and scar- 
let fever. This condition is explained by the fact that the 
bacteria of the disease have produced in the blood a new sub- 
stance, which prevents a subsequent growth of the same kind 
of bacteria in that person. To this new product has been 
given the name of antitoxine, and this method of Nature's for 
protection against disease is now utilized both in its cure and 
in its prevention. The period during which any person who 
has had the disease is protected from future attacks, varies in 
different persons and in different diseases. 



6. Toxines and ptomaines, how produced ? 

7. Antitoxine, its nature and effect ? 



358 BACTERIA AND DISEASE 

8. Destruction of Bacteria. — Not everybody, however, who 
is exposed to these disease-producing germs falls a victim to 
them. Many persons are continually exposed to contagious 
diseases and infections of various kinds, and yet do not get the 
disease. There must then be a natural mode of destroying the 
bacteria after they find access to the body. This power of 
destroying bacteria is said to exist in the white cells of the 
blood. In addition there exists, no doubt, in the fluid portion 
of the blood, the plasma, a chemical power to destroy bacteria. 

8. The natural mode of destroying bacteria ? 



APPENDIX 

THE CARE OF THE SICK-ROOM 

The sick-room should be bright and airy, and "sweetness and 
light " its motto. Other things being equal, it is best on one of the 
upper floors — <in the case of some "catching" disease on the top 
floor. Let it be on the sunny side of the house. If for any reason 
the light of the sun is temporarily to be avoided — as when the 
eyes are sensitive or have been operated upon — let the light be shut 
out by a proper arrangement of blinds or curtains. The air-supply to be 
breathed by the sick person should be pure. Those who, in health, find 
themselves in an impure air can quit it ; they are not compelled to suffer 
from it ; but a sick person may be incapable of recognizing the bad 
quality of the air, as well as helpless to free himself from it. 

To keep the air pure, the windows should be opened as often as three 
times a day, care being taken to protect the patient from being chilled, 
while the room is being aired. 

Unless the physician should direct differently, one window — that most 
remote from the bed — should be open an inch or more both day and 
night, and in all seasons. The extent to which the sash should be lowered 
must be governed largely by the weather and the direction of the wind. 

A fire, in an open fireplace, except in summer weather, will be a great 
help towards keeping the air pure. The upward current through a chim- 
ney-flue, if unobstructed, is equal to or not far below 20,000 cubic feet 
per hour; an outlet sufficient for a room occupied by ten persons. 

The inlet of air, however, must not be forgotten, otherwise the air in 
the room tends to become both impure and too thin. As our houses are 
generally constructed, the inlet of air is best secured by a window-sash 
being lowered from the top. 

Take special care that no stationary wash-basin or other sewor-eon- 
nected convenience is improperly plumbed, and that sower gas cannot by 
any possibility escape into the sick-room. 

The swinging of doors to create a current is not an efficient means of 
ventilation, as it agitates the air of tin 1 room without purifying it. and 
often disturbs the patient. 

350 



360 APPENDIX 

A draught of air is to be avoided ; it will seldom occur that the air of 
the room requires to be so speedily changed that the patient need be 
exposed to a draught ; never, when care has been taken to provide con- 
tinuous and gradual ventilation. 

It should be borne in mind that cold air is not necessarily pure air, 
and that ventilation is not less needed in winter than in warm weather. 

Sleep is a great necessity to the sick. If a well person slumbers in the 
day-time, it will interfere with his sound repose at night, but with the 
sick this is generally not the case. The more they sleep the more favor- 
able are the chances for their recovery : so that it will be readily seen 
how important it is to avoid noise and jar in the sick-room, especially if 
the disease is acute. 

Bear in mind that even slight noises, as the rustling of garments, the 
creaking of doors, whispering, or noisy footfalls, may be sufficient to dis- 
turb a brain that is rendered sensitive by pain or wakef alness. 

The clothing next the skin should be changed more frequently in sick- 
ness than in health. These changes must be quickly and deftly made, 
and with as little disturbance as possible. 

Under some conditions of disease, the best welfare of the patient is 
accomplished by having two beds in the room instead of one. 

The temperature of the room must be watched. To that end a ther- 
mometer should always be present, and easily approached. It is better 
not to have it directly in the view of the patient. The temperature 
should not be allowed to vary much from 65° F., unless the doctor other- 
wise directs. 

Let the furniture be as plain and as free from upholstery as possible ; 
not many pieces are required. Movable carpets or rugs are better than 
those that are permanently laid. Curtains about the windows are out of 
place in a sick-room : so are flowering plants and birds, as a general rule. 
Florence Nightingale, however, makes an exception in the case of chronic 
invalids, and consents to the comforting influence of a pet bird or two. 

In regard to the admission of visitors, and conversation, much will 
depend upon the strength of the patient and the kind of sickness: at 
many times these are to be forbidden, as having a disquieting influence. 
When contagious disease is in the house, the sick-room must be avoided 
by all except those who have the care of the patient, and those having 
this care should avoid coming in contact with the other members of the 
household, especially the children. 

Bear in mind that everything brought in contact with the sick is liable 
to endanger the health of the well. 

No articles in use by the invalid should be removed or used by others 
until thoroughly disinfected ; the dishes and spoons should be put in boil- 
ing water before being taken from the room. The room itself should be 
fumigated with sulphur when the person is removed from it. 



APPENDIX 361 

Old pieces of muslin, etc., should be used instead of handkerchiefs to 
receive the poisonous discharges from the nose, mouth, and throat. 
These can be destroyed by fire, and thus prevent the danger of conveying 
the disease to others. 

" Taking the breath " and kissing should be avoided by those in atten- 
dance upon the case. 

The bottles of medicine and other reminders of illness should, as far 
as convenient, be withdrawn from the view of the sick. 

Such as are to be kept always at hand should be arranged in an 
orderly way upon a tidily- covered bed-side table. The sight of a siphon 
bottle of aerated water is agreeable to most patients ; that may be kept 
in the room, but the vessels containing milk, drinking-water, etc., should 
be kept elsewhere. 

DISINFECTION 

Filth fosters or produces certain diseases ; it should, therefore, be 
removed as soon as possible. When it is difficult to remove it, dis- 
infectants come into play, as they have the power to rob it of some of 
its disease-breeding force. But let it be remembered that disinfection is not 
cure ; it is not a substitute for cleanliness and pure air. The true cure is 
the removal of filth ; and when our homes are concerned in some question 
of drainage where the filth is out of our sight, it may be necessary to 
consult and employ the plumber or some other artisan. 

In times gone by, it was the custom to mask bad smells by burning 
pastilles, coffee, cascarilla, and the like. These are not now much used; 
for most persons have come to understand that the fumes thus created do 
not remove, but simply overpower the evil odors. 

Chemistry has advanced to such a point that various pungent chemical 
substances, formerly not well known, can be furnished at small cost, and 
these substances have the power, in varying degrees, to check vile odors. 
Carbolic acid, chloride of lime, and Labarraque's solution are among the 
best known of these, but there are also certain of the salts of iron, and 
zinc, and permanganate of potash that may be used. Sulphur is much 
used for the fumigation of rooms that have been infected. 

Another cheap disinfectant is a solution of chloride of lead. It is in- 
odorous, effective, and the cost is small. Take half a drachm of the 
nitrate and dissolve it in a pint or more of boiling water. Dissolve two 
drachms of common salt in a pail or bucket of water ; pour the two solu- 
tions together and allow the sediment to sink. A cloth dipped in this 
solution, and hung up in a room, will correct a bad odor promptly, or if 
the solution be thrown down a drain, or upon foul-smelling refuse, it will 
have the same effect. 

The room to be purified with sulphur should be made as tight as pos 
siblc, so that no fumes can escape, either by window, door, or chimney. 



362 APPENDIX 

Put three pounds of sulphur in an iron pot, which should not stand upon 
woodwork or carpet, lest they be burned, but in a large pan of ashes, or 
upon a layer of bricks ; on this sulphur pour a tablespoonful of alcohol. 
This is then set on fire, and everybody immediately withdraws from the 
room. The room should remain closed ten hours, after which it should be 
thoroughly aired before it is occupied, for the fumes of the sulphur are 
irritating to the lungs. 

The chemicals above mentioned should be known and labelled as 
poisons. Many persons have been injured, if not killed, by incautiously 
or ignorantly drinking those that are of a liquid form. 

Heat is one of the best, if not the best, disinfecting agent. Articles of 
bedding and furniture that cannot well "be treated otherwise can be puri- 
fied by a long exposure to a temperature of 240° F. In some cities, es- 
pecially in England, furnaces are made for the reception of bulky articles 
that have become infected. 

Fresh air is another powerful agent. If woven fabrics, clothing, and 
the like are for a long time aired out of doors, they cease to be infective ; 
probably by the enormous dilution, if not destruction, of the elements of 
danger. 

Certain diseases are "catching" ; they have the power of spreading 
from one person to another, chiefly by the particles that pass off from the 
body of the patient. Among these diseases are small-pox, measles, 
scarlet fever, and diphtheria. The articles that are worn or used by the 
patient become "infected," and they should be disinfected before they 
are used by others. As a rule, of course, a doctor will be called in to 
attend to these diseases. When that is so, follow his directions as to dis- 
infection, as well as wery other part of the treatment of the case. For 
substances that are not injured by being washed, a good and cheap dis- 
infectant is sulphate of zinc (" white vitriol ") and common salt dissolved 
in water, boiling hot if possible, using eight tablespoonfuls of the zinc, 
and four of salt to the gallon of water. This is useful for clothing, bed- 
linen, towels, handkerchiefs, etc. After these articles have lain for an 
hour or two in this solution, they should be allowed to stand in boiling 
water before being washed. Infected articles that are of little value 
should, of course, be destroyed by fire. 

The United States Treasury Department has published the following 
formula for the disinfection of the rags coming from Egypt: "1. Boiling 
in water for two hours under a pressure of fifty pounds per square inch ; 
2. Boiling in water for four hours without pressure ; or, 3. Subjection to 
the action of sulphur fumes for six hours, burning one and one-half to 
two pounds of roll-brimstone in each 1,000 cubic feet of space, with the 
rags well scattered upon racks." Any one of these three methods is 
accepted as sufficiently thorough to prevent the spreading of cholera by 
means of rags. 



APPENDIX 363 



THE HOME AND HEALTH 



The location of the house should be airy, dry, and sunny. 

A certain amount of elevation is necessary, in order to secure proper 
drainage. Too much shade must not fall upon the house, as sunlight is 
very necessary to a proper degree of animal vigor. Young children, as 
is well known, especially profit by the tonic influence of sunlight. 

The cellar is an important part of the dwelling ; therefore, unless care 
be taken for its ample ventilation, it will be the source from which is sup- 
plied much of the air breathed in the upper chambers of the house. If 
the cellar is damp the house is liable to become so, and if vegetables are 
stored in the cellar, an especial degree of care is needed to ventilate it 
thoroughly and constantly. 

House Drainage. — An English writer has stated that "the most 
important part of the house is the drains." This, no doubt, sounds 
strangely to the ears of many, who have been brought up to view the 
parlor or drawing-room as the true centre of the house ; and yet it is no 
foolish saying, when we reflect that with a bad system of drainage to a 
house every dweller therein stands in peril of several forms of disease 
that, mild as the cases may be, are a source of anxiety, and when severe, 
too often have a fatal termination. Drain-diseases, such as typhoid 
fever, dysentery, diphtheria, and scarlet fever, often destroy entire fami- 
lies. These diseases do not always come upon a home through defective 
drainage, but when they do, they frequently show themselves in a very 
violent form. 

Drainage (as applied to dwellings) consists in conveying away from 
the house the liquid and solid impurities that would otherwise accumulate 
in or near the dwelling. Waste is a necessary accompaniment of all 
animal life, to the preparation and taking of food, to the clothing of the 
body, to bathing and other simple acts of daily life. The waste material 
of houses tends to decay and to become offensive. It must, therefore, 
not only be put out of sight and smell, but must be removed so far away 
that it cannot return in the form of dangerous, invisible gases of decom- 
position. 

The best house-drains are made of iron or glazed earthenware, care- 
fully selected and well laid. The joints of the pipes should be gas-tight. 
The soil-pipe should be carried up to and through the roof. All the 
waste-pipes from basins, etc., in the rooms should be joined in a gas-tight 
manner to the soil-pipe, and each and every basin and other tixtuve 
should have a separate trap. What is a trap? It is a device that is 
designed to retain a certain portion of the water running through it — 
called the "water-seal 11 — so that the ascent oi air or gas, from the drain 
back into the room, is prevented. It "traps" the sewer gas away from 
us. Whenever a, fixture has boon used ami there is not, beyond all 



364 APPEXDIX 

doubt, a sufficiency of water to fill the trap, additional water should be 
poured in. Traps are of various sizes, and of an infinite variety of pat- 
terns and patents, and must vary greatly according to their situation ; 
but one thing should be made sure of in their use — namely, that they 
hold not less than two inches of water as a " seal." 

There is at almost all seasons of the year an upward, because warmer, 
current of air through the main pipes. It is therefore better to have a 
fresh-air inlet pipe near the point where the drain leaves the house-wall. 
This helps to prevent the unsealing of traps. It also brings about a 
purer condition of the air in the interior of the system of pipes — so use- 
ful in this air-current through the soil-pipe that if applied there is little 
danger of the escape of sewer gas into the living rooms. 

What is sewer gas or sewer air ? It varies greatly in different places 
and at different times. It is not a definite gas, like oxygen, nitrogen, 
etc., but varies in composition, and what is still more worthy of note, it 
varies in its dangerous qualities. It is not always offensive, although it 
is generally so ; its odor has been described as being " sweetish and sick- 
ish." Its dangerous qualities have not yet been determined by chemistry 
or the microscope, but one practical point may be borne in mind — 
namely, that when a case or cases of contagious disease occur in any 
house along any given line of sewer pipes, it is best to use disinfectants 
in the drainage of the other dwellings along the same line of sewer. 
Children should avoid playing over or around the sewer-gratings in the 
streets at all times, and especially when scarlet fever and like contagious 
diseases are known to be in the neighborhood ; for the exit of sewer air 
at these points is always very free, unless it be directly after rainfall. 

One other point must be remembered — that the best-laid system of 
house-plumbing is not indestructible. In the course of time, defects will 
arise, breaks will occur ; for this reason it would be well for every house- 
holder to have an examination made at intervals, of every joint and along 
the whole line of the house connection with the sewer or drain. 

It is thought by many that sewer gas is not found in the country 
because there are no sewers — they have been misled by the word. If 
the words "drain air" or "filth gas" had been adopted, the universal 
production of this injurious substance, in close connection with every 
abode of man, wherever located, might have been better understood. In 
country houses there are, perhaps, fewer dangers of contamination of the 
air we breathe by waste products, because there are fewer water-closets, 
wash-basins, sinks, etc. , and the rooms are less exposed to impure air. 

But in the country danger is apt to come by or through the pollution 
of the water supply. The well, which furnishes that cool and refreshing 
draught, is the point to be watched. It is convenient to have the well near 
the house, because when the snow is on the ground and the weather is 
cold, the distance to the well from the house is a matter of no small 



APPENDIX 365 

moment. Near the house must be the stable and pens for animals — the 
waste from the house goes upon the ground, and not very far away from 
the house — the chamber slops and the more offensive matters go into 
a pit, which must not be too distant. The result of all these conditions 
is a pollution of the soil at all these points — a pollution which spreads 
with every rainfall, and which, sooner or later, reaches the well ; yet the 
water may appear as pure as ever. It only remains to have the suitable 
disease-germ lodged in this .polluted territory to bring down the whole 
household with a fever. This is the kind of soil-pollution which is hard 
to cure, and which, in long-settled countries, causes laws to be enacted 
requiring all vaults for the reception of house and human waste to be 
made water-tight, so as to save the soil from its poisoning influence. 

This is the kind of poisoning which, in the Dark Ages, caused so much 
unrighteous persecution of the innocent. In those days, no care whatever 
was taken in the towns, high-walled, crowded, and unsewered, to protect 
the water supply from pollution — as a result, some terrible epidemic of 
fever would arise. Then the angry populace would, in their ignorance, 
cry out : " The Jews have poisoned the wells." The wells were poisoned, 
no doubt, but the Jew was no more worthy of blame than were his ac- 
cusers. Nevertheless, the Jews were not spared — they were robbed, 
imprisoned, executed. 

Drainage in the city is a comparatively easy problem when the city's 
sewers are laid in the streets. In the country it is more difficult, and on 
this account the fewer fixtures or " modern improvements " there are in 
the house the better it will be. There should be no less care within the 
country house, where waste-pipes are put in, than in the city house. The 
material should be well selected, tightly joined, and properly ventilated. 
The water-closet should be remote from the house. Earth closets are 
better than the ordinary vaults — house-waste from kitchen and laundry 
should be taken to a considerable distance from the house, and far away 
from the well, and either deposited in a water-tight cesspool, or convoyed 
away, by a system of subsoil drainage tiles, arranged so as to fertilize 
some unoccupied plot of ground. 

ON GOING INTO THE COUNTRY 

To spend the summer in the country would be the choice of all city 
dwellers, whenever their purses will permit of it. And there are not a 
few advantages in such a course ; tin' change of scene is good, the moun- 
tains and the seaside give a purer and cooler air — an air that invigorates 
and aids in restful sleep at night, so different from the midsummer atmos- 
phere in hot cities. There are fewer excitements in the country ; we do 
not u live so fast," and there is full scope for healthful life and activity in 
the open air, with the green and blue of nature all about us, instead of 
the monotonous walls of towering houses. 



366 APPENDIX 

But this course, pleasant and helpful to so many, is not without its 
danger. Many who go away for a vacation are brought home sick on 
account of fever or other sickness caused by defects and faults of drain- 
age existing in these temporary summer homes. Scarcely a year goes by 
that one or more summer resorts have not gained the ill name of being 
the hotbeds of typhoid fever, dysentery, and the like. 

In view of this, how important it becomes that we exercise judgment, 
and seek skilled advice in the selection of our summering places. 

Again, there is another clanger that must not be overlooked. Let us 
suppose that the summer vacation has passed by without accident ; that 
we return invigorated by the experience, and that the home in the city 
has been empty and closed during our absence ; what has happened that 
the air in the rooms newly reopened should be foul and stifling ? This 
has taken place : the water that stands in the traps of house pipes, and 
shuts off gases from the sewer when the rooms are in use and water is 
daily entering the different wash-basins, etc. , has during our absence been 
evaporated. For weeks, perhaps, there has been no " water-seal " in the 
traps, and the ascent of sewer air has been going on continuously, so that 
not only is the air utterly unfit to live in, but all the curtains, carpets, and 
other absorbing materials have become saturated with the pollution thus 
allowed to enter. Let it be remembered that when a sink, etc., is not in 
use, it is gradually losing the trap-water by the evaporation. 

What is the remedy, you will ask, for the condition of things caused by 
closing up the house, as above stated ? To this the reply is, that the house 
should from time to time be opened and aired, and water should be poured 
down each and every sanitary fixture, in sufficient quantity to renew the 
supply of water in the trap of each. 



APPENDIX 



367 



EXERCISES FOR HOME GYMNASTICS 

(See jiag-e 45) 




Fig. 1. — Position for Exercising 




Fig. 2. — To develop Muscles 
the Upper Back 




Fig. 8.— To develop Fkont Akm, Chest,' 
Abdomen, Front Leg 




Vu:. 4. To DEVELOP Low ik BaC 
am> Middi r Back 



No,,, ; The cuts of the above Illustrations were kindl, tarnished In- the 6ferra«nset1 
Machine Company, manufacturers or .ho apparatus, Providence, R.I. m ™B»m*M 



368 



APPENDIX 





Fig. 5. — To develop Back Upper Arm 



Fig. 6. — To develop Chest Muscles 
and Front Arm 





Fig. 7. — To develop Side- waist 
Muscles 



Fig. 8. — To develop Upper and 
Lower Back, Shoulder, Back 
Arm, and Back Leg 



APPENDIX 



369 







Fig. 9. — To develop Abdomen; to deepen the Thorax 




Fig. 10. — To widen the Thorax and develop the Sides of Waist 




Fig. 11. — To develop tiie Abdominal Muscles am> the Muscles of Uppeb Leg 



GLOSSARY 



Ab-do'men (Latin abdo, to conceal). The largest cavity of the body, 
containing the liver, stomach, intestines, etc. ; the belly. 

Ab-sor'bents (L. ab and sorbeo, to suck up). The vessels which take 
part in the prooess of absorption. 

Ab-sorp'tion. The process of sucking up fluids by means of an animal 
membrane. 

Ac-com-mo-da'tion of the eye. The alteration in the shape of the crys- 
talline lens, which accommodates or adjusts the eye for near and 
remote vision. 

Ac'id, Lactic (L. lac, milk). The acid ingredient of sour milk ; the gas- 
tric juice also contains it. 

Al-bu'men, or Albumin (L. albus, white). An animal substance resem- 
bling white of egg. 

Al-bu'mi-nose (from albumen). A soluble animal substance produced 
in the stomach by the digestion of the albuminoid substances. 

Al-bu'min-oid substances. A class of proximate principles resembling 
albumen ; they may be derived from either the animal or vegetable 
kingdoms. 

Al'i-ment (L. alo, to nourish). That which affords nourishment ; food. 

Al-i-ment'ary Ca-nal (from aliment). A long tube in which the food is 
digested, or prepared for reception into the system. 

An-aes-thet'ics (Greek &v, an, without, alo-dvaia, aisthesia, feeling). 
Those medicinal agents which prevent the feeling of pain, such as 
chloroform, laughing-gas, etc. 

An-i-mal'cule (L. animal' culum, a small animal). Applied to animals 
which can only be seen with the aid of the microscope. Animalculum 
(plural, animalcula) is used with the same meaning. 

A-or'ta (Gr. aopreoixcu, aorteomai, to be lifted up). The largest artery of 
the body, and main trunk of all the arteries. It arises from the left 
ventricle of the heart. The name was first applied to the two large 
branches of the trachea, which appear to be lifted up by the heart. 

A'que-ous Humor (L. aqua, water). A few drops of watery colorless 
fluid occupying the space between the cornea and crystalline lens. 

A-rach'noid Mem'brane (Gr. apdxvv, arachne, a cobweb, and eldos, eidos, 

370 



GLOSSARY 371 

like). An extremely thin covering of the brain and spinal cord. It 

lies between the dura mater and the pia mater. 
Ar'bor Vi'tse (L). Literally, "the tree of life"; a name given to the 

peculiar appearance presented by a section of the cerebellum. 
Ar'ter-y (Gr. a-qp, aer, air, and rripeiv, terein, to contain). A vessel by 

which blood is conveyed away from the heart. It was supposed by 

the ancients to contain air ; hence, the name. 
Ar-tic-u-la'tion (L. articulo, to form a joint). The more or less movable 

union of bones, etc.; a joint. 
A-ryt'e-noid Car'ti-la-ges (Gr. dpvraiva, arutaina, a pitcher). Two small 

cartilages of the larynx, resembling the mouth of a pitcher. 
As-sim-i-la'tion (L. ad, to, and similis, like). The conversion of food 

into living tissue. 
Au-di'tion (L. audio, to hear). The act of hearing sounds. 
Au'di-to-ry Nerve. One of the cranial nerves ; it is the special nerve 

of hearing. 
Au'ri-cle (L. auris, the ear). A cavity of the heart. 
Bar'i-tone (Gr. (3apvs, barus, heavy, and tovos, tonos, tone). A variety of 

male voice between the bass and tenor. 
Bel-la-don'na (It. beautiful lady). A vegetable narcotic poison. It has 

the property of enlarging the pupil, and thus increasing the brilliancy 

of the eye ; so called from its use by Italian ladies. 
Bi-cus'pid (Ij. bi, two, and cuspis, prominence). The name of the 

fourth and fifth teeth on each side of the jaw ; possessing two 

prominences. 
Bile. The gall, or peculiar secretion of the liver ; a viscid, yellowish 

fluid, and very bitter to the taste. 
Bron'chi (Gr. (3p6yxos, bronchos, the windpipe). The two first divisions 

or branches of the trachea ; one enters each lung. 
Bron'chi-al Tubes. The smaller branches of the trachea within the sub- 
stance of the lungs, terminating in the air-cells. 
Bron-chi'tis (from bronchia, and itis, a suffix signifying inflammation). 

An inflammation of the larger bronchial tubes; a "cold" affecting 

the lungs. 
Cal-ca're-ous (L. calx, lime). Containing lime. 
Ca-nal' (L.). In the body, any tube or passage. 
Ca-nine' (L. canis, a dog). Name given to the third tooth on each side of 

the jaw ; in the upper jaw it is also known as the eye-tooth, pointed 

like the tusks of a dog. 
Cap'il-la-ry (L. capil'lus, a hair, capilla'ris, hair-like). The name of 

the extremely minute blood-vessels which conned the arteries with 

the veins. 
Car'bon Di-ox'ide (COg). Chemical name for carbonic acid gas. 
Car-bon'ic A'cid. The gas which is present in the air expired from the 



372 GLOSSARY 

lungs ; a waste product of the animal kingdom, and a food of the 

vegetable kingdom. 
Car'di-ac (Gr. KapdLa, kardia, the heart). The cardiac orifice of the 

stomach is the upper one, and is near the heart ; hence its name. 
Car-niv'or-ous (L. ca'ro, flesh, and vo'ro, to devour). Subsisting upon flesh. 
Ca-rot'id Ar'ter-y. The large artery of the neck, supplying the head 

and brain. 
Car'ti-lage. A solid but flexible material, forming a part of the joints. 

air-passages, nostrils, etc. ; gristle. 
Ca'se-ine (L. ca'seus, cheese). The albuminoid substance of milk; it 

forms the basis of cheese. 
Cer-e-bel'lum (diminutive for cer'ebrum, the brain). The little brain, 

situated beneath the posterior third of the cerebrum. 
Cer'e-brum (L.). The brain proper, occupying the entire upper portion 

of the skull. It is nearly divided into two equal parts, called "hemi- 
spheres," by a cleft extending from before backward. 
Cho'roid (Gr. x^ ov i chorion, a membrane or covering). The middle 

tunic or coat of the eyeball. 
Chyle (Gr. x^^i chalos, juice). The milk-like fluid formed by the 

digestion of fatty articles of food in the intestines. 
Chyme (Gr. x v ^i chumos, juice). The pulpy liquid formed by digestion 

within the stomach. 
Cil'i-a (pi. of cil'i-um, an eyelash). Minute, vibratile, hair-like pro- 
cesses found upon the cells of the air-passages, and other parts that 

are habitually moist. 
Cir-cu-la'tion (L. cir'culus, a ring) . The circuit, or course of the blood 

through the blood-vessels of the body, from the heart to the arteries, 

through the capillaries into the veins, and from the veins back to 

the heart. 
Co-ag-u-la'tion (L. coag'ulo, to curdle). Applied to the process by 

which the blood clots or solidifies. 
Coch'le-a (L. coch'lea, a snail-shell) . The spiral cavity of the internal ear. 
Con'cha (Gr. kovxv, konche, a mussel-shell). The external shell-shaped 

portion of the external ear. 
Con-junc-ti'va (L. con and jun'go, to join together). A thin layer of 

mucous membrane which lines the eyelids and covers the front of the 

eyeball ; thus joining the latter to the lids. 
Con-trac-til'i-ty (L. con and tra'ho, to draw together). The property of 

muscle which enables it to contract, or draw its extremities closer 

together. 
Con-vo-lu'tions (L. con and vol'vo, to roll together). The tortuous 

foldings of the external surface of the brain. 
Con-vul'sion (L. convel'lo, to pull together), A more or less violent agi- 

tation of the limbs or body. 



GLOSSARY 373 

Cor'ne-a (L. cor' mi, a horn). The transparent, horn-like substance which 

covers the anterior fifth of the eyeball. 
Cor'pus-cles, Blood (L. dim. of cor'pus, a body). The small bi-concave 

discs which give to the blood its red color ; the white corpuscles are 

globular and larger. 
Cos-met'ic (Gr. ko<x/j.€oj, kosmeo, to adorn). Beautifying ; applied to 

articles which are supposed to increase the beauty of the skin, etc. 
Cra'ni-al (L. cra'nium, the skull). Pertaining to the skull. The nerves 

which arise from the brain are called cranial nerves. 
Cri'coid (Gr. k/h'/cos, kri'Jcos, a ring). A cartilage of the larynx resembling 

a seal-ring in shape. 
Crys'tal-line Lens (L. crystal'lum, a crystal). One of the so-called 

humors of the eye ; a double convex body situated in the front part of 

the eyeball. 
Cu'ti-cle (L. dim. of cu'tis, the skin). The scarf-skin; also called the 

epider'mis. 
Cu'tis (L. skin or hide). The true skin, lying beneath the cuticle ; also 

called the der'mis. 
De-cus-sa'tion (L. decus'sis, the Roman numeral ten, X). A reciprocal 

crossing of fibres from side to side. 
Di'a-phragm (Gr. diacppdaau, diaphrasso, to divide by a partition). A 

large, thin muscle which separates the cavity of the chest from the 

abdomen ; a muscle of respiration. 
Dif-fu'sion of Gases. The power of gases to become intimately mingled, 

without reference to the force of gravity. 
Duct (L. du'co, to lead). A narrow tube ; the thoracic duct is the main 

trunk of the absorbent vessels. 
Du-o-de'num (L. duode'ni, twelve). The first division of the small intes- 
tines, about twelve fingers' breadth long. 
Du'ra Ma'ter (L.). Literally, the hard mother; the tough membrane 

which envelops the brain. 
Dys-pep'si-a (Gr. 5us, dus, difficult, and Tre-n-Tw, pepto, to digest). Diffi- 
cult or painful digestion ; a disordered condition of the stomach. 
E-mul'sion (L. emul'geo, to milk). Oil in a finely divided state sus- 
pended in water. 
En-am'el (Fr. email). The dense material which covers the crown of 

the tooth. 
Endocardium (Gr. <^5o, endo, within, and KapSla, kardia, the heart. The 

lining membrane of the heart. 
En'er-gy, Specific, of a Nerve. When a nerve of special sense is excited, 

whatever be the cause, the sensation experienced is that peculiar to 

the nerve; this is said to be the law of the specific energy of the 

nerves. 
Ep-i-glot'tis (Gr. iirl, epi\ upon, and ^Xwrns, glottis, the entrance to the 



374 GLOSS AM? 

windpipe). A leaf -shaped piece of cartilage which covers the top of 

the larynx during the act of swallowing. 
Ex-cre'tion (L. excer'no, to separate). The separation from the Wood of 

the waste particles of the body ; also the materials excreted. 
Ex-pi-ra'tion (L. expi'ro, to breathe out). The act of forcing air out of 

the lungs. 
Ex-ten'sion (L. ex, out, and ten'do, to stretch). The act of restoring a 

limb, etc. , to its natural position after it has been flexed, or bent ; the 

opposite of Flexion. 
Fe-nes'tra (L.). Literally, a window; the opening between the middle 

and internal ear. 
Fi'brine (L. Ji'bra, a fibre). An albuminoid substance found in the 

blood ; in coagulating it assumes a fibrous form. 
Flex'ion (L.flecto, to bend). The act of bending a limb, etc. 
Fol'li-cle (L. dim. of foV lis, a bag). A little pouch or depression in a 

membrane ; it has generally a secretory function. 
Fun'gous Growths (L. fun'gus, a mushroom). A low grade of vegetable 

life. 
Gan'gli-on (Gr. ydyy\i.ov, ganglion, a knot). A knot-like swelling in the 

course of a nerve ; a smaller nerve-centre. 
Gas'tric (Gr. yaaT-qp, g aster, stomach). Pertaining to the stomach. 
Gland (L. glans, an acorn). An organ consisting of follicles and ducts, 

with numerous blood-vessels interwoven ; it separates some particular 

fluid from the blood. 
Glos'so-phar-yn-ge'al Nerve (Gr. y\£><r<ra, glossa, the tongue, and <pdpvy%, 

pharunx, the throat). The nerve of taste supplying the posterior third 

of the tongue ; it also supplies the throat. 
Glu'ten (L.). Literally, glue ; the glutinous albuminoid ingredient of 

wheat. 
Gran'ule (L. dim. of gra'num, a grain). A little grain ; a microscopic 

object. 
Gus-ta'tion (L. gusto, to taste). The sense of taste. 
Gust'a-to-ry Nerve. The nerve of taste supplying the front part of the 

tongue, a branch of the " fifth " pair. 
Hem'or-rhage (Gr. alp.a, hai'ma, blood, and pr/yw/xL, regnumi, to burst). 

Bleeding, or the loss of blood. 
Hem-i-ple'gi-a (Gr. tj/xlo-vs, hemisus, half, and tt\t)<t<tu, plesso, to strike). 

Paralysis, or loss of power, affecting one side of the body. 
Hem'i-spheres (Gr. acpalpa, sphaira, a sphere). Half a sphere, the lateral 

halves of the cerebrum, or brain proper. 
He-pat'ic (Gr. jjwap, hepar, the liver). Pertaining to the liver. 
Her-biv'o-rous (L. her'ba, an herb, and vo'ro, to devour). Applied to 

animals that subsist on vegetable food. 
Hu'mor (L.). Moisture: the humors are transparent contents of the 

eyeball. 



GLOSSARY 375 

Hy-dro-pho'bi-a (Gr. vSup, hudor, water, and <poj3ew, phobeo, to fear). A 
disease caused by the bite of a rabid dog or other animal. In a person 
affected with it, convulsions are occasioned by the sight of a glittering 
object, like water, by the sound of running water, and by almost any 
external impression. 

Hy'gi-ene (Gr. vyieia, hugieia, health). The art of preserving health and 
preventing disease. 

Hy'per-o'pi-a. Abbreviated from Hy'per-me-tro'pi-a (Gr. virep, huper, 
beyond, ptrpov, metron, the measure, and u>\p, ops, the eye). A defect 
of vision dependent upon a too short eyeball ; so called because the 
rays of light are brought to a focus at a point behind the retina ; the 
true "far sight." 

In-ci'sor (L. inci'do, to cut). Applied to the front teeth of both jaws, 
which have sharp cutting edges. 

In'cus (L.). An anvil ; the name of one of the bones of the middle ear. 

In-sal-i-va'tion (L. in, and sa-li'va, the fluid of the mouth). The min- 
gling of the saliva with the food during the act of chewing. 

In-spi-ra'tion (L. in, and spi'ro, to breathe). The act of drawing in the 
breath. 

In-teg'u-ment (L. in, and te'go, to cover). The skin, or outer covering 
of the body. 

In-tes'tine (L. in'tus, within). The part of the alimentary canal which 
is continuous with the lower end of the stomach ; also called the intes- 
tines, or the bowels. 

I'ris (L. i'ris, the rainbow). The thin muscular ring which lies between 
the cornea and crystalline lens, and which gives the eye its brown, 
blue, or other color. 

Ju'gu-lar (L. ju'gulum, the throat). The name of the large veins which 
run along the front of the neck. 

Lab'y-rinth (Xafivpivdos, laburin'thos, a building with many winding pas- 
sages). The very tortuous cavity of the inner ear, comprising the 
vestibule, semi-circular canals, and the cochlea. 

Lach'ry-mal Apparatus (L. lach'ryma, a tear). The organs for forming 
and conveying away the tears. 

Lac'te-als (L. lac, lac'tis, milk). The absorbent vessels of the small 
intestines ; during digestion they are filled with chyle, which lias a 
milky appearance. 

La-ryn'go-scope (Gr. \dpvy%, larunx, the larynx, and (ncoirtio, skopeo, to 
look at). The instrument by which the larynx may be examined in 
the living subject. 

Lar'ynx (Gr.) The cartilaginous tube situated at the top of the wind- 
pipe, or trachea ; the organ of the voire. 

Lens (L.) Literally, a lentil ; a piece 1 of transparent glass or other sub- 
stance so shaped as either to converge or disperse the rays of light. 



376 GLOSSARY 

Lig'a-ment (L. li'go, to bind). A strong, fibrous material binding bones 

or other solid parts together ; it is especially necessary to give strength 

to joints. 
Lig'a-ture. A thread of silk or other material used in tying around an 

artery. 
Lymph (L. tym'pha, spring-water). The colorless, watery fluid conveyed 

by the lymphatic vessels. 
Lym-phat'ic Vessels. A system of absorbent vessels. 
Mal'le-us (L.). Literally, the mallet ; one of the small bones of the mid- 
dle ear. 
Mar 'row. The soft, fatty substance contained in the central cavities of 

the bones : the spinal marrow, however, is composed of nervous tissue. 
Mas-ti-ca'tion (L. mas'tico, to chew). The act of cutting and grinding 

the food to pieces by means of the- teeth. 
Me-dul'la Ob-lon-ga'ta. The " oblong marrow," or nervous cord, which 

is continuous with the spinal cord within the skull. 
Mem-bra'na Tym'pan-i (L.). Literally, the membrane of the drum; a 

delicate partition separating the outer from the middle ear ; it is 

sometimes incorrectly called the drum of the ear. 
Mem'brane. A thin layer of tissue serving to cover some part of the 

body. 
Mi'cro-scope (Gr. [unpos, mikros, small, and aKoirtu, skopeo, to look at). 

An optical instrument which assists in the examination of minute 

objects. 
Mo'lar (L. mo'la, a mill). The name applied to the three back teeth 

of each side of the jaw ; the grinders, or mill-like teeth. 
Mo'tor (L. mo'veo, mo' turn, to move). Causing motion; the name of 

those nerves which conduct to the muscles the stimulus which causes 

them to contract. 
Mu'cous Mem'brane. The thin layer of tissue which covers those inter- 
nal cavities or passages which communicate with the external air. 
Mu'cus. The glairy fluid which is secreted by mucous membranes, and 

which serves to keep them in a moist condition. 
My-o'pi-a (Gr. /xvu, miw, to contract, and u>\p, ops, the eye). A defect of 

vision dependent upon an eyeball that is too long, rendering distant 

objects indistinct ; near-sight. 
Na'sal (L. na'sus, the nose). Pertaining to the nose ; the nasal cavities 

contain the distribution of the special nerve of smell. 
Nerve (Gr. vevpov, neuron, a cord or string). A glistening, white cord of 

cylindrical shape, connecting the brain or spinal cord with some other 

organ of the body. 
Nerve Cell. A minute, round and ashen-gray cell found in the brain and 

other nervous centres. 
Nerve Fi'bre. An exceedingly slender thread of nervous tissue found in 



GLOSSARY 377 

the various nervous organs, but especially in the nerves ; it is of a 

white color. 
Nu-tri'tion (L. nu'trio, to nourish). The processes by which the nour- 
ishment of the body is accomplished. 
CE-soph'a-gus (Gr.). Literally, that which carries food; the tube lead- 
ing from the throat to the stomach ; the gullet. 
O-le-ag'i-nous (L. o'leum, oil). Of the nature of oil: applied to an 

important group of food principles — the fats. 
01-fac'to-ry (L. olfa'cio, to smell). Pertaining to the sense of smell. 
Oph-thal'mo-scope (Gr. 6<pda\fx6s, opJithalmos, the eye, and <tkott{u, skopeo, 

to look at). An instrument devised for examining the interior of the 

globe of the eye. 
Op'tic (Gr. dpdw, dij/ofxcu, fut. opsomai, to see). Pertaining to the sense 

of sight. 
Or'bit (L. or'bis, the socket). The bony socket or cavity in which the 

eyeball is situated. 
Os'mose (Gr. wa-p-os, osmos, a thrusting or impulsion). The process by 

which liquids are impelled through a moist membrane. 
Os'se-ous (L. os, a bone). Consisting of, or resembling bone. 
Pal'ate (L. pala'tum, the palate). The roof of the mouth, consisting of 

the hard and soft palate. 
PaPmar. Relating to the palm of the hand. 
Pan'cre-as (Gr. irav,pan, all, and Kptas, kreas, flesh). A long, flat gland 

situated near the stomach ; in the lower animals the analogous organ 

is called the sweet-bread. 
Pa-piPlae (L. papil'la). The minute prominences in which terminate 

the ultimate fibres of the nerves of touch and taste. 
Pa-ral'y-sis. A disease of the nervous system marked by the loss of 

sensation, or voluntary motion, or both ; palsy. 
Par-a-nle'gi-a (Gr. irapairXr/aau}, paraplesso, to strike amiss). A form of 

paralysis affecting the lower half of the body. 
Pa-tel'la (L. dim. of pat'ina, a pan). The knee-pan ; a small bone. 
Pel'vis (L.). Literally, a basin; the bony cavity at the lower part of 

the trunk. 
Pep'sin (Gr. irtivTu, pepto, to digest). The organic principle of the 

gastric juice. 
Per-i-car'di-um (Gr. wept, peri, and Kapdla, kardia, the heart). A porous 

membrane enclosing the heart, and secreting a lubricating fluid. 
Per-i-stal'tic Move'ments (Gr. TrepKrrAXw, peristello, to contract). The 

slow, wave-like movements of the stomach and intestines. 
Per-i-to-ne'um (Gr. irepLrelvw, periteino, to stretch around). The invest- 
ing membrane of the stomach, intestines, and other abdominal organs 
Per-spi-ra'tion (L. perspVro, to breathe through). The sweat, or watery 

exhalation of the skin ; when visible, it is called sensible perspiration ; 

when invisible, it is called insensible perspiration. 



378 GLOSSARY 

Pe'trous (Gr. irtrpa, petra, a rock). The name of the hard portion of the 
temporal bone, in which is situated the drum of the ear and labyrinth. 

Phar'ynx (Gr, <pdpvy£, pharunx, the throat). The cavity between the 
back of the mouth and gullet. 

Phys-i-ol'o-gy (Gr. ipvais, phusis, nature, and \6yos, logos, a discourse). 
The science of the functions of living, organized beings. 

Pi'a Ma'ter (L.). Literally, the tender mother; the innermost of the 
three coverings of the brain. It is thin and delicate ; hence the name. 

Pleu'ra (Gr. -n-Xevpd, a rib). A membrane covering the lung and lining 
the chest. There is one for each lung. 

Pleu'ri-sy. An inflammation affecting the pleura. 

Pneu-mo-gas'tric (Gr. irvevfupp, pneumon, the lungs, and yaar-qp, gaster, 
the stomach). The name of a nerve distributed to the lungs and 
stomach ; it is the principal nerve of respiration. 

Pneu-mo'ni-a (Gr.). An inflammation affecting the air-cells of the 
lungs. 

Pres-by-o'pi-a (Gr. irpeapvs, presbus, old, and a>\p, ops, the eye). A defect 
of the accommodation of the eye, caused by the hardening of the 
crystalline lens ; the "far-sight" of adults and aged persons. 

Proc'ess (L. proce'do, proces'sus, to proceed, to go forth). Any projec- 
tion from a surface. Also, a method of performance ; a procedure. 

Pty'a-lin (Gr. irrvaXov, ptualon, saliva). The peculiar organic ingre- 
dient of the saliva. 

Pul'mo-na-ry (L. pul'mo, palmo'nis, the lungs). Pertaining to the lungs. 

Pulse (L. peVlo, pul'sum, to beat). The striking of an artery against 
the ringer, occasioned by the contraction of the heart, commonly felt 
at the wrist. 

Pu'pil (L. pupiVla). The central, round opening in the iris, through 
which light passes into the depths of the eye. 

Py-lo'rus (L. irvXmos, puloros, a gate-keeper). The lower opening of 
the stomach, at the beginning of the small intestine. 

Re'fiex Action. An involuntary action of the nervous system, by which 
an external impression conducted by a sensory nerve is reflected, or 
converted into a motor impulse. 

Res-pi-ra'tion (L. res'piro, to breathe frequently). The function of 
breathing, comprising two acts : inspiration, or breathing in, and 
expiration, or breathing out. 

Ret'i-na (L. re'te, a net). The innermost of the three tunics or coats of 
the eyeball, being an expansion of the optic nerve. 

Sac'cha-rine (L. sac'charum, sugar). Of the nature of sugar; applied 
to the important group of food substances which embraces the dif- 
ferent varieties of sugar, starch, and gum. 

Sa-li'va (L. ). The moisture or fluids of the mouth, secreted by the 
salivary glands, etc. 



GLOSSARY 379 

Scle-rot'ic (Gr. tr/cX^o's, skleros, hard). The tough, fibrous outer tunic 
of the eyeball. 

Se-ba'ceous (L. se'bum, fat). Resembling fat; the name of the oily- 
secretion by which the skin is kept flexible and soft. 

Se-cre'tion (L. secer'no, secre'tum, to separate). The process of separat- 
ing from the blood some essential important fluid ; which fluid is 
also called a secretion. 

Sem-i-cir'cu-lar Canals. A portion of the internal ear. 

Sen-sa'tion. The perception of an external impression by the nervous 
system ; a function of the brain. 

Sen-si-bil'i-ty, General. The power possessed by nearly all parts of the 
human body of recognizing the presence of foreign objects that come 
in contact with them. 

Se'rum (L.). The watery constituent of the blood, which separates from 
the clot during the process of coagulation. 

Skel'e-ton (Gr.). The bony framework of an animal, the different parts 
of which are maintained in their proper relative positions. 

Spec'tro-scope (from spec'trum and o-/co7rew, skopeo, to examine the spec- 
trum). An instrument employed in the examination of the spectrum 
of the sun or any other luminous body. 

Sphyg'mo-graph (Gr. acpvy/mos, sphugmos, the pulse, and ypd(pw, grapho, 
to write). An ingenious instrument by means of which the pulse is 
delineated upon paper. 

Sta'pes (L.). Literally, a stirrup ; one of the small bones of the tympa- 
num, or middle ear, resembling somewhat a stirrup in shape. 

Sym-pa-thet'ic System of Nerves. A double chain of nervous ganglia, 
connected together by numerous small nerves, situated chiefly in front 
of and on each side of the spinal column. 

Syn-o'vi-a (Gr. <rvv, sun, and wov, oon, egg, resembling an egg). The 
lubricating fluid of joints, so called because it resembles the white of 
egg. 

Sys'to-le (Gr. owtAXw, sustello, to contract). The contraction of the 
heart, by which the blood is expelled from that organ. 

Tac-tile (L. tac'tus, touch). Relating to the sense of touch. 

Tem'po-ral (L. tem'pus, time, and tem'pora, the temples). Pertaining to 
the temples; the name of an artery; so called because the hair 
begins to turn white with age in that portion of the scalp. 

Ten'don (L. ten'do, to stretch). The white, fibrous cord or band by 
which a muscle is attached to a bone ; a sinew. 

Tet'a-nus (Gr. rehoj, teino, to stretch). A disease marked by persistent 
contractions of all or sonic of the voluntary muscles ; those of the jaw 
are sometimes solely affected ; the disorder is then termed locked-jaw, 

Tho'rax (Gr. 6upa$, thorax, a breast-plate). The upper cavity of the 
trunk of the body, containing the lun^s, heart, ete. ; the chest. 



380 GLOSSARY 

Thy'roid (Gr. Ovpeos, thureos, a shield). The largest of the cartilages of 
the larynx ; its angular projection in the front of the neck is called 
"Adam's apple." 

Tra'che-a (Gr. rpaxvs, trachus, rough). The windpipe, or the largest of 
the air-passages ; composed in part of cartilaginous rings, which render 
its surface rough and uneven. 

Trans-fu'sion (L. transfun'do, to pour from one vessel to another). The 
operation of injecting blood taken from one person into the veins of 
another ; other fluids than blood are sometimes used. 

Tri-chi'na Spi-ra'lis (L.). A minute species of parasite or worm, which 
infests the flesh of the hog, and which may be introduced into the 
human system by eating pork not thoroughly cooked. 

Tym'pa-num (Gr. rv/uLwavop, tumpanon, a drum). The cavity of the 
middle ear, resembling a drum in being closed by two membranes, 
and in having communication with the atmosphere. 

U're-a (Gr.). A substance secreted from the blood by the kidneys. 

U'vu-la (L. uva, a grape). The small pendulous body attached to the 
back part of the palate. 

Vas'cu-lar (L. vas'calam, a little vessel). Pertaining to, or containing, 
blood-vessels. 

Ve'nous (L. ve'na, a vein). Pertaining to, or contained within, a vein. 

Ven-ti-la'tion. The introduction of fresh air into a room or building in 
such a manner as to keep the air within it in a pure condition. 

Ven-tril'o-quism (L. veyi'ter, the belly, and lo'qaor, to speak). A modifi- 
cation of natural speech by which the voice is made to appear to come 
from a distance. The ancients supposed that the voice was formed in 
the belly ; hence the name. 

Ven'tri-cles of the heart. The two largest cavities of the heart, situated 
at its apex or point. 

Ver'te-bral Column (L. ver'te-bi-a, a joint). The back-bone, consisting of 
twenty-six separate bones, called vertebrae, firmly jointed together ; 
also called the spinal column and spine. 

Ves'ti-bule. A portion of the internal ear, communicating with the semi- 
circular canals and the cochlea ; so called from its fancied resemblance 
to the vestibule or porch of a house. 

Vil'li (L. vil'lus, the nap of cloth). Minute thread-like projections found 
upon the internal surface of the small intestine, giving it a velvety 
appearance. 

Vit're-ous (L. vi'trum, glass). Having the appearance of glass; applied 
to the humor occupying the largest part of the cavity of the eyeball. 

Viv-i-sec'tion (L. vi'vus, alive, and se'co, to cut). The practice of oper- 
ating upon living animals, for the purpose of studying some 
physiological process. 

Vocal Cords. Two elastic bands or ridges situated in the larynx ; they 
are the essential parts of the organs of the voice. 



INDEX 



Abducens nerves 226 

Absorbent vessels 137-139 

Absorption by the blood-vessels 137 

by the lacteals 138, 141 

of food 140-141 

Nature of. 117, 136 

Accidents, First help in ... . 342-353 

Accommodation, Function of 302-303 

Achilles, Tendon of 36 

Adam's apple 323 

Adipose tissue 39 

A gue-cake 145 

Air, Atmospheric 195-196 

Amount of in lungs 200 

Carbonic acid in 203-204, 206 

Changes in, from respiration 196-198 

Dust in the 202-203 

Effects of impure 204-206 

Impurities in 201 

Nature's provision for purifying 207 

Air-cells of the lungs 189-192 

Air-passages of the lungs 18S-192 

Albinos 60 

Albumen S2 

of the blood 152 

Albuminoid substances S2 

Coagulation of 82 

Digestion of. 133 

Properties of. 82 

Varieties of S2 

Alcohol, Abnormal movements due to.. 52 

as a fat producer 179-180 

as a food 109-1 10 

as a medicine 1 14 

as a ration 109 

destructive to life 112 

Effects of, on brain 261 

Effects of, on body temperature... 110-111 

Effects of, on digestion 145-1 16 

Effects of, on the heart 179-1 so 

Effects of, on the kidneys 1-17 

BffeotS of, on the liver. ." 146 

Kffeots of, on the mind 252 

KlTVots of, on the inn ados 51 



PAGE 

Alcohol, Effects of, on respiration 214 

Effects of, on the special senses.. ..315-316 

for thirst 110 

History of 108 

Hereditary desire for 260 

impairs the will 252-253 

Kinds of. 108-109 

Properties of. 109 

Proper and improper use of 112-113 

Poisonous effects of. 254 

Spontaneous combustion and 213-214 

Strength and 50-51 

Trembling due to 251 

Alcoholic beverages, Use of. 114-115 

Alcoholism, Chronic 255 

Alimentary canal 119 

A moeba 14 

Anatomy 13 

Animal functions 217-218 

Control of, by cerebro-spinal system.. 219 

Animal heat, Production of 211-213 

Regulation of 212 213 

Animals, Relative strength of 40 

Antidotes for poison 350-353 

Antitoxine 357 

Apoplexy 244 

Appendicitis 136 

Apple of the eye 294 

Aquaria 209 

Aqueous humor 292, 299 

Arachnoid membrane '22[ 

Arbor vitse 225 

Arterial blood L58, L98 199 

differs from venous 199-200 

Arteries, Arrangement o\' 167-168 

Carotid 169 

Hepatic 176 

Histology of 168 

Pulsation of 169-170 

Radial 169 

Temporal 1 69 

Articulations 23 

Arytenoid cartilage — 824 

A sphyxia 349 

Assimilation, Process of. : .117. 177 



881 



382 



INDEX 



tage 

Astigmatism: 304 

Auditory canal 308 

Auditory nerves 226, 312-313 

Auricles of the heart 161-162, 164 

Axis cylinder of nerve-fibres 219 

B 

Backbone 25 

Bacteria 355 

causing disease 355-357 

Destruction of 358 

Bathing, among the ancients 68 

Importance of 64 

Time and manner of 67 

Baths, Kinds of 66 

Belladonna, Use of, af a cosmetic 295 

Bicuspid teeth 121 

Bile, Accumulation of, in gall-bladder. . . 134 

, Secretion of. 134-135 

Uses of 135 

Bladder 144 

Bleeding, how stopped 178-179, 343 

Blind-spot 296 

Blood, Arterial 158, 198-199 

Change of color in 158 

Circulation of 159 

Coagulation of 155-156 

Color of 152 

Composition of 152, 156 

Corpuscles of 152-155 

Differences between venous and arte- 
rial 199 

Histology of 152 

Importance of 151 

Passage of, through the heart 163-164 

Eespiratory changes in 198 

Supply of, in brain 221 

Yenous 171-172 

Blood-vessels, Absorption by 137 

Injuries to 178 

Blushing 231 

Body, Eenovation of the 95 

Bone-corpuscle , 22 

Bones, Form and composition of 17-18 

Growth of 27 

Histology of _. 21-22 

of the ear 310 

Eepair of 27-28 

Structure of 19-20 

Uses of 7 

Bow-legs 29 

Brain 219-225 

Effects of alcohol on 251 

Functions of the 251 

Injuries to the 246-247 

Membranes of the 221 

Keflex action of the 249-250 

Structure of the 219, 221 

Bread 102-108 

Breath of sick persons 202-203 



PAGE 

Broken limb, Management of 28-29 

Bronchial tubes 1S9 

Bronchitis 192 

Burns, Treatment of 346 

C 

Caffeine 106 

Canal, Alimentary 119 

Canals, Semicircular 312 

Canine teeth 121 

Capillary blood-vessels 172-174 

Circulation in the 173 

Carbon dioxide, exhaled from the lungs. 196 

in the air 203-204, 206, 207 

Eetention of, in the blood 199 

Carotid artery 169 

Cartilage, Arytenoid 324 

Cricoid , 323 

Inter-vertebral 26 

Kinds of. 26 

of the joints 24 

Thyroid 323 

Caseine 83 

Cataract 299 

Cells 13-14 

Ciliated 191 

Epithelial 140 

Life of 58-60 

Motion of 16 

Nerve 219, 231-232 

Nourishment of 15 

Eeproduction of 15 

Eespiration of 200 

Structure of 14 

Cerebellum, Function of ." 245 

Structure of 224-225 

Cerebro-spinal fluid 221 

Cerebro-spinal nervous system 219 

Cerebrum, Function of 245-24S 

Structure of 222-223 

Cheese S3 

Chest, Contents of 23 

Framework of 22 

Chloral hydrate, Effects of. 25S 

Chloroform, Uses of 259 

Chocolate 108 

Choke-damp 203 

Chorea 242 

Choroid coat of the eye 293 

Chyle 135 

Chyme 133 

Cigarette smoking 257 

Cilia 191-192 

Ciliary muscle 303 

Circulation 117, 151-181 

in a frog's foot 173 

in the veins 171-172 

of the blood 159 

Eapidity of . , 175-176 

The portal division of. ............. i-< 1T6, 



INDEX 



383 



PAGE 

Circulation, The pulmonary division 

of 176, 187 

through the heart 163-164 

Climate, Adaption to 212 

Effect of, on appetite 84, 85, 96 

Clothing 69-70 

Rules regarding 71 

Coagulation of blood 155-156 

Coats of the eye 292 

Cocaine 259 

Coccyx 25 

Cochlea 313 

Coffee 87,106 

Effects of 107 

Collar-bone 23 

Colon 136 

Color-blindness 298 

Alcohol and 315-316 

Column, Spinal 25-26 

Columns of the spinal cord 227 

Complexion . . . . 60 

Concha of the ear 307 

Conjunctiva • 289 

Consumption and foul air 205-206 

Contraction of the heart 162 

Contraction of muscles 37-39 

Convulsions, Cause of 242 

Treatment of 348 

Convolutions of the cerebrum 322-323 

Cooking 99-100 

Cords, Yocal 324-325 

Cornea 292 

Corpuscles, Blood 152-155, 19S 

Cosmetics 71-72 

Country, On going into the 365-366 

Cranial ganglia 245 

Cranial nerves 225-227 

Cranium 221 

Cricoid cartilage 323 

Crystalline lens 298-301 

Elasticity of 303 

Uses of 299-301 

Cuticle 56-57 

Modified forms of 5S 

Office of 272 

Cutis ! 57-58 

D 

Decussation of motor and sensory fibres 

Of spinal cord 287-288, 244 

Delirium tremens 255, 816 

Dentine 120 

Dentition of infancy 120 

Dialysis, Process of 14(1 

Diaphragm 22 

Movements of, in respiration 192 

Diastole of I he heart 162 

Diet, The best SS 

Mixed 95 '.'7 

Necessity of u regulated SS 



PAGE 

Diet, Variety in 89 

Digestion 117-148 

Circumstances affecting 141-143 

Effects of alcohol on 145-146 

Gastric 132-133 

General plan of 119 

how affected by tobacco 147 

Intestinal 134-141 

Nature of 118 

The saliva and 124-128 

Disease, Bacteria causing 355-357 

Germs of, in the breath 202-203 

Diseases, of the lungs 192 

Respiratory, among the intemperate.. 214 

Disinfectants and cleanliness 201 

Disinfection 361-362 

Dislocations 344-345 

Drain diseases 363 

Drainage 363-365 

at summer resorts 366 

Drowning, Treatment in cases of 349 

Drugs, Hereditary desire for 260 

Drum of the ear 309 

Duct, Nasal , 291 

Thoracic 139 

Dura mater 221 

Dyspepsia 128 

£ 

Ear 306 

Bones of the 310 

Cavities of the 312 

Drum of the 30S-309 

External 307-30S 

Foreign bodies in 315 

Internal 312-313 

Middle 308-312 

Ear for music 322 

Eaf-sand 812-818 

Ear-stones 812 

Ear-wax 304 

Removal of 315 

Eggs, Composition of 98 

Emotion, Effects of, on the heart 165 

Emulsion of fats in digestion 185 

Endocardium t'»l 

EndoSmOSiS, Process of 139 

Epiglottis, Uses of. 190, 824 

Epidermis 56-51 

Eustachian tube 810 312 

Exeroise, Effects of n 42 

Excessive 48, 45 

Importance of 41 

Modes of 43. 45-49 

Exosmosis, Process of 140 

Expiration 198 

Extensor muscles 86 

Eye, Astigmatism of the 304 

Defective formation of the 801-804 

Power oi\ of accommodation 302 808 



384 



INDEX 



PAGE 

Eye, Structure of the 2ST-801 

Sympathetic inflammation of 287 

Eyeball 291-293 

Eyelashes 2S9 

Eyelids 2S8-2S9 

F 

Facial nerves 226 

Fainting 342-343 

Far-sight 302 

Fats, Emulsion of S3 

in food 84 

Fenestra oralis 313 

Fibres, Muscular 33-34 

Nervous 219 

Fibrin in food 83 

of the blood 152, 155-156 

Fire-damp 203 

Fish as food 101 

Poisonous 353 

Fits 348 

Flexor muscles 36 

Follicles 137 

Food, Absorption of 140-141 

Animal 97-101 

Daily quantity of 93-94 

Experiments as to S9 

Inorganic substances in 77-81 

Necessity for 91 

Organic substances in S1-S7 

Source of 75 

Yegetable 101-104 

Foods, Comparative digestibility of. .131-132 

Fractures 28-29, 344-345 

Frost-bites 34S 

Fruits as food 104 

Functions, Animal and vegetative. ..217-218 

G 

Ganglia 219 

cranial, Function of 245 

of the sympathetic system 230 

Gall-bladder 134 

Gas, Illuminating 347 

Suffocation by 347 

Gases, Interchange of, in the lungs 199 

Poisonous, in the air 201 

Gastric digestion 132 

Gastric juice, Action of. 129-130 

Daily quantity of 130 

Germs, Disease, in the breath 202-203 

See also Bacteria. 

Glands, Function of US 

Lachrymal 290 

of the ear 308 

Perspiratory 61-62 

Salivary 124-125 

Sebaceous 60-61 

Types of US 

Glossopharyngeal nerves 226, 277 



PAGE 

Gluten 83 

Glycogen 140, 176 

Grog 109 

Gullet 128, 190 

Gum as food S7 

Gustatory nerves 277 

Gymnastics and health 46 

Home 47^9 

in schools and colleges 45-47 

H 

Hair 5S-59 

Uses of 59 

Hand, Mechanism of the 36 

Harvey, William 159 

Hasheesh 259 

Haversian canals 21 

Health, Gymnastics and 46 

Light aiid 69-70 

Hearing, Effects of alcohol on 316 

Injury to 314-315 

Organ of. 306-313 

Protection of. 313-314 

Relation of, to speech 322 

Sense of, and sound 305-306 

Heart 160-161 

Action of the 162-163 

Activity of the 166-167 

Cavities of the 161, 164 

Circulation in the 163-164 

Effects of alcohol on the 179-1 SO 

Effects of tobacco on the 1S1 

Valves of the 164 

Heart-beats, Frequency of ..164-165, 169-170 

Heart muscle 35 

Heat, Animal, Production of. 211 

Regulation of 212-213 

Hemiplegia 23S 

Hemispheres of the cerebrum 222 

Hemorrhage 343 

Hepatic artery 176 

vein 176 

Heredity. Desires resulting from 260 

House, Proper location of 363 

Humor, Aqueous 292, 299 

Vitreous 292, 299 

Hunger, Sensation of 92-93, 244 

Hydra 218 

Hydrochloric acid 130 

Hydrophobia 242 

Hygiene 13 

Hyperopia 301-302 

Hypoglossal nerves 227 

I 

Ileo-ca?cal valve 136 

Illuminating gas 347 

Incisor teeth 120 

Incus 310 

Inorganic substances in food 77 



INDEX 



\m 



PAGE 

Insalivation 124-128 

Insects, Antidote for poison of 353 

Insensible perspiration 62 

Inspiration 192 

Intestinal juice, Action of 135 

Intestines 134-141 

Digestion in small 134-136 

Mucous membrane of. 135-136 

The large 136 

Villi of the 137 

Iris 293-295 

Iron, Properties of, in the blood 81 

Properties of, in food 81 

J 

Joints 23-24 

Classification of 24 

Juice, Gastric 129-130 

Intestinal 135 

Pancreatic 134 

K 

Kerosene, Accidents from . . 347 

Kidneys 144 

Effects of alcohol on the 147 

Knock-knees 29 

L 

Labyrinth 312-313 

Lachrymal fluid 290 

gland 290-291 

point 291 

Lacteals, Absorption by 138-139 

Lactometer 90 

Laryngoscope 326 

Larynx, Production of the voice in 326 

Kapid growth of 327 

Structure of 189-190, 323-326 

Lens, Crystalline 298-301 

The convex 334 

Ligaments 23 

Suspensory, of the eye 294 

Light, Effects of, on health 69 

in the sick room 70 

Theory of 2S6 

Lime, Importance of 81 

in the bones SO 

in the food S0-81 

Liver, Circulation in 176 

Effects of tobacco on 146-147 

Secretion of 134 

Locked jaw 242 

Long-sight 301-302 

Lungs, Capacity of 194 

Diseases of 192 

Interchange of gas in 1 99 

Structure of 1ST 192 

Lymph 189, 177-178 

Lymphatic duct 1 IS 

Lymphatic vessels 139. 177-1T8 



PAGE 

M 

Magendie on pain 268 

Magnesia, Compounds of, in food 81 

Malleus 310 

Marrow 19 

Spinal 227 

Mastication 119-128 

Importance of 127 

Meats, Cooking and preservation of 98-99 

Medulla oblongata, Functions of the. 243-244 

Structure of the 221, 225 

Membrana tympani 309 

Membrane, Arachnoid 221 

Dura mater 221 

Mucous 135-136, 190- J91 

Pia mater 221 

Microscope, Accessories to 336, 337 

Choice and use of 336-338 

Compound 335-336 

Necessity of 333 

Preliminary studies with 337-340 

Simple .- 334-335 

Milk, as a food 97 

Composition of 97 

Specific gravity of 98 

Milk-teeth 120 

Moderation Societies 113-114 

Molar teeth 121 

Morphine 257 

Motor nerves 234-236 

Mould 356 

Mucous membrane of the air passages . 190-191 

of the intestines 135-136 

Muscles 33 

Contraction of 37-39 

Effect of alcohol on 51-52 

Flexion and extension of 35-36 

skeletal, Structure of 33-34 

visceral, Structure of 35 

Muscular contraction 37-39 

fibres 33-34 

sense 276 

Myopia : 301-302 

N 

Nails, Care of the 65 

Structure of the 68 -59 

Uses of the 59 

Narcotics, and digestion 268 

("raving for 260 

Kinds of 257 

sloop produced by 260 

Use of 260 

Nasal cavities 286-281 

duct 291 

Nerve, Croat sympathetic 281 

Nerve-cells 219 

Nerve-fibres 219 

Properties of 28 

Sensory and motor 284-286 



386 



INDEX 



PAGE 

Nerve-impulses 219 

Nervous centres 219 

Nervous system 217-260 

Cerebro- spinal 219 

Structure of the 218-219 

Nervous tissue, Properties of 231-233 

Nerves, Abducens 226 

Auditory 226, 312-313 

Cranial 225-227 

Facial 226 

Functions of 233-236 

Glossopharyngeal 226, 277 

Gustatory 277 

Hypoglossal 227 

Oculomotorius 225 

Olfactory 225, 281-2S2 

Optic 225,286 

Patheticus 226 

Pneumogastric 227, 244 

Spinal 228-229 

Spinal accessory 227 

Nicotine 256 

Night-air 210 

Nose 2S1 

Nutrition, Processes of 1.17-118 



Oculomotorius nerves 225 

Oesophagus 128 

Oils, Emulsion of 83 

in food 84 

Old-sight 304 

Olfactory nerves 225, 281-282 

Opiates, Effects of 258 

Opium, Physiological effects of 257-258 

Optic nerves 225, 2S6 

Specific energy of 296 

Orbicular bone 310 

Orbit of the eye 288 

Organic substances as food 81 

Organs of circulation 160 

of digestion 119 

of hearing 306 

of respiration 187-188 

of sight 287-2S8 

of speech .. 323 

of the animal functions 218 

Osmosis, Process of 139 

Ossicles 309 

Oxidation 208 

Oxygen, Amount of, absorbed daily 200 

and animal heat 211 

Effect of, on venous blood 198-200 

in respiration 186 

in the cells 200 

P 

Pain, Relation of, to pleasure 268 

Sensation of 267 

Use of. .,,,.... 267-269 



PAGE 

Palsy of drunkards 316 

Pancreatic juice, Uses of the 134-135, 137 

Pancreatin 135 

Papillae, of the cutis 58 

of the tongue 277 

Sensitory nerves in 271 

Paralysis 238 

Paraplegia 236 

Patheticus nerves 226 

Pelvis 22 

Pepsin 130 

Peptone 133 

Pericardium 161 

Perimysium 33 

Peristaltic action of the stomach 131 

Peritoneum 134 

Perspiration, Effects of interrupted 62-64 

Sensible and insensible 62 

Uses of 62 

Perspiratory glands 61-62, 118 

Physical culture 44 

Physiology, Human 13 

Pia mater 221 

Plasma, Composition of 152 

in the tissue cells 177-178 

Pleura 188 

Pleurisy 192 

Pneumogastric nerves 227, 244 

Pneumonia 192 

Poisons and their antidotes 350-353 

Portal vein 176 

Posture, Habits of 29 

Potash in food 81 

Potato 103 

Presbyopia 304 

Protoplasm 14-15 

Ptomaines 357 

Ptyalin 126 

Pulsation of the arteries 168, 169 

of the heart 166, 169 

Pulse 164, 169-170 

Pulse- writer 170 

Pupil of the eye 294 

Pyloris 129 

R 

Eadial artery 169 

Eecreation 47 

Eed corpuscles of the blood 152-153 

Reflex action of brain 249-250 

Reflex action of the spinal cord 238 

Excess of 242 

Requisites for 240 

Uses of 240-243 

Rennet 83 

Respiration, Amount of labor in 200-201 

Control of 19* 

Effect of alcohol upon 214 

Effect of, on the blood 198 

Frequency of . . . , ,....,..,..... 193 



INDEX 



387 



PAGE 

Eespiration, Movements of 192-193 

Object of 187 

Organs of 187-192 

Eest, Necessity for 49-50 

Eetina 295-298 

Eetinal images, Character of 299-301 

Endurance of 296-297 

Eibs, Movements of, in respiration 192 

S 

Saccharine substances 85 

Sacrum 25 

St. Vitus's Dance 242 

Sarcolemma 34 

Saliva, Action of, in digestion 124-128 

Action of, on the teeth 123 

Secretion of. 124 

Salivary glands 124-125 

Salt, Common 78-80 

Importance of, as food 79-80 

Scalds, Treatment of 346 

Scars from burns 346-347 

Sclerotic coat of the eyeball. 293 

Sea-bathing 66-67 

Sebaceous glands 60-61, 118 

Semicircular canals 312, 313 

Sensations, of pain .267-268 

of temperature 275 

of weight 275 

Production of 264-265 

Special 269-271 

Variety of. 265 

Sense of hearing 305-315 

of sight 285-304 

of smell 280-2S4 

of taste 276-280 

of touch 58, 271-275 

Muscular 276 

Thermal 275 

Sensibility, General, of the body 266 

Sensory nerves 234-236 

Serpent, Antidote for poison of 353 

Sewers, Dangers from 364 

Shock, Treatment for 842 

Short-sight 301-302 

Sick-room, Care of 359-361 

Sight, Effect of alcohol on 316 

Effect of tobacco on 816 

Function of 285 

Loss of 2S7 

Nerve of 2S6 

Organ of 287-301 

Sinews 86-87 

Skeleton 22-23 

Changes in the 28-29 

Skin, Care of the 65 

Structure of the 66 

Skull, The, and Its uses 22-23 

Sleep, Amount required 50 

Necessity for 49 



PAGE 

Smell, Nerve of 281-282 

Organ of. 280-281 

Eelation of, to taste 279-280 

Uses of 282-284 

Smoking, Effects of • .255-256 

Cigarette 257 

Snuff-taking 257 

Soda in food 81 

Sound, Theory of 305-306 

Special senses, Mutual relations of 270 

Spectroscope 153 

Speech, Eelation of, to hearing 322 

The voice and 321-322 

Sphygmograph, The 170 

Spleen 145 

Spinal accessory nerves 227 

Spinal column 25 

Curvature of the 26-27 

Spinal cord, Direction of fibres in .. .237-238 

Functions of . . , 236-237 

Membranes of 221 

Eeflex action of 238-243 

Structure of 227-228 

Spinal nerves 228-229 

Origin of the 227 

Spontaneous combustion 213 

Alcohol the cause of 213-214 

Sprains 23 

Treatment of 346 

Stapes 310 

Starch, Change of, into sugar 87 

in food 86 

Properties of 86 

Stimulating substances 87 

Stimulation, Effects Of mild 253 

Stomach 128-129 

Digestion in 132-133 

Movements of 131 

Secretions of 129-130 

Strength, Alcohol and 50-51 

Physical 40 

Suffocation 199 

by illuminating gas 847 

Sugars, Source of, in food 85 

Varieties of 85-86 

Sun-bath 68-69 

Sunstroke ;US 

Sympathetic system 219, 280-231 

Systole of the heart 162 

T 

Tact us erudltus 275 

Taste, Education of 280 

Effeot of alcohol on 816 

Organ of _7t'< 271 

Eelation of, to other souses 279-280 

Sense of -77 -7S 

Tea, Effeotsof 87, 107-108 

Tears 290-291 

Teeth, Arrangement of 121 



388 



INDEX 



PAGE 

Teeth, Bicuspid . . ._. 121 

Canine 121 

Incisor 120 

Molar 121 

of different animals 122 

Preservation of 123 

Eenewal of 120 

Structure of 120 

Temperature, Extremes of 213 

of animals 211 

of the body 212, 213 

of the sick room 360 

Sensation of 275 

Temporal artery 169 

Tendon of Achilles 36 

Tendons 34, 36-37 

Tetanus 242 

Theine 107 

Theobroma 108 

Thermae 68 

Thirst, Nature of 92-93 

Nervous organ of 244 

Thoracic duct 139 

Thorax 139 

Throat-deafness 312 

Thyroid cartilage 323 

Tickling. 266 

Tissues, Law of the 333 

Microscopic study of human 339 

of inferior animals 339-340 

Tobacco as a poison 256 

Effect of, on digestion 147 

Effect of, on the heart 181 

Effect of, on the young 256 

Tobacco-heart 256 

Tongue 276-278 

in speech 327 

Touch, Delicacy of 274-275 

Organs of. 271-272 

Eelation of, to taste 279 

Sense of. 58, 272-274 

Toxines 357 

Trachea 18S-189 

Transfusion of blood 157 

Traps in drains 363 

Trichina spiralis 101 

Trunk 22 

Trypsin 135 

Tunics of the eyeball 292 

Tympanum of the ear .308-312 

U 

Urea 144 

Ureter 144 



PAGE 

V 

Valves, Ileocecal 136 

of heart 164 

of the veins 171 

Vapor of exhaled breath 196 

Vegetable food 96, 101 

Vegetative functions 21 7-218 

Sympathetic system and 219 

Vein, Hepatic 176 

Portal 176 

Veins, Structure of 170-171 

Vena cava 176 

Venous blood 158, 198-199 

Change of, in respiration 200 

Ventilation 209-210 

of the cellar 363 

of the sick room 360-361 

Ventricles of the heart 161-162 

of the larynx 325 

Ventriloquism 329-330 

Vermiform appendix 136 

Vertebra 25 

Vertigo 343 

Vestibule of the ear 312-313 

Villi, Absorption by 137-138 

A T ital knot 244 

Vocal cords 189, 324-325 

Voice and speech 321-322 

Organ of 323-326 

Production of 326-327 

Eange of 328 

Varieties of 327 

W 

Walking as a means of exercise 43 

Waste, Eepair and 91, 92 

Waste-pipes 363 

Water, Action of, on lead 105-106 

from springs and wells 104-105 

in exhaled breath 196 

Proportion of, in the tissues and fluids 

of the body 77 

Purity of 104 

Water-seal 363 

Weight, Sensation of 275 

Wells, Pollution of 364-365 

White corpuscles of the blood 154 

Winking 291 

Y 
Yeast 856 



JUL 2- i 



!902 









LIBRARY OF CONGRESS 




